US-Iran War: What the UN Fact-Finding Mission Can and Cannot Do

The United Nations fact-finding mission examining Iran has produced some of the most consequential international findings of the war: it says Iranian authorities committed grave violations that amount in many cases to crimes against humanity, while finding “reasonable grounds” to believe that U.S. forces committed war crimes in two February 2026 strikes. But the mission is an investigative body, not a criminal court. It can collect evidence, assess alleged violations, preserve documentation and put findings before the international community; it cannot convict defendants, issue criminal sentences or automatically impose consequences on the United States or Iran.

That distinction is crucial. The latest report can strengthen the evidentiary record for future proceedings, increase diplomatic pressure and give national prosecutors or other institutions material to examine. It cannot, by itself, establish individual criminal liability. Whether the findings ultimately lead to prosecutions, reparations or other forms of accountability depends on jurisdiction, evidence, cooperation and political decisions by states and international institutions.

What the UN mission is

The Independent International Fact-Finding Mission on the Islamic Republic of Iran was established by the UN Human Rights Council to investigate alleged human-rights violations in Iran. The Council has previously extended the mission’s mandate specifically so that evidence could be documented, verified, consolidated and preserved. It has also called on Iran to cooperate and provide access and information necessary for the mission’s work.

Its role is therefore fundamentally investigative.

The mission can interview witnesses, analyze available evidence, examine satellite imagery and videos, assess weapons and other physical evidence, and compare individual allegations to broader patterns of conduct.

It can then make findings about whether the available evidence provides sufficient grounds to conclude that particular violations may have occurred.

That function becomes especially important when investigators cannot freely enter the country or obtain records directly from the authorities accused of wrongdoing.

What the latest investigation found

The September 2026 findings cover both Iran’s internal crackdown and conduct during the war.

On the domestic side, the mission reported killings by security forces across all 31 Iranian provinces, the deaths of at least 221 children, tens of thousands of arbitrary detentions, allegations of torture and solitary confinement, and circumstances raising concerns about enforced disappearances. It also documented executions connected to the protests and concluded that many of the violations amounted to crimes against humanity, including murder, imprisonment, torture and other inhumane acts.

On the international-conflict side, investigators found “reasonable grounds” to believe that the United States committed war crimes in two strikes: an attack on the Shajareh Tayyebeh Primary School in Minab and another involving a sports complex in Lamerd. The mission said the attacks killed or injured civilians and damaged civilian objects.

The two categories should be kept legally separate. The alleged crimes against humanity concern the conduct of Iranian authorities toward civilians, while the U.S. allegations concern the conduct of military operations during an armed conflict and the rules governing attacks.

What “reasonable grounds” actually means

One of the most important phrases in the latest report is “reasonable grounds to believe.”

It is an investigative formulation, not a criminal conviction.

The mission is effectively saying that, after examining the evidence available to it, investigators believe there is a sufficiently credible factual basis for the allegation. A later criminal prosecution would require another institution to establish jurisdiction, identify the accused and prove the required elements of the offense under the applicable legal standard.

That distinction matters particularly in the allegations concerning the U.S. military.

The mission concluded that the Minab school was visibly identifiable as a civilian facility and that the United States failed to take all feasible measures to verify that it was a military objective. Investigators characterized the alleged conduct as going beyond mere negligence.

But the report does not itself constitute a judicial ruling that an American service member, commander or political official is criminally responsible.

What it can do: build an evidentiary record

Perhaps the mission’s most important function is evidence preservation.

In conflicts involving restricted access, communications blackouts and competing accounts, evidence can disappear quickly. Investigators may therefore preserve material that could later be examined by courts or other accountability mechanisms.

For the Iran investigation, the evidence includes witness accounts, verified videos, satellite imagery and weapons analysis. The mission relied on such material partly because Washington and Israel did not provide investigators with access to personnel or respond to their requests for information concerning the U.S. strikes.

That does not make every finding immune from challenge. Additional evidence could confirm, modify or contradict particular conclusions.

But creating a consolidated record has long-term value. A future prosecutor does not necessarily have to begin with an empty file simply because the original investigation was conducted by a UN fact-finding body rather than a court.

What it can do: identify patterns

Fact-finding missions are also useful because individual incidents can look very different from a pattern of conduct.

One detention might be described as an isolated security measure. Hundreds or thousands of similar arrests, combined with allegations of torture, denial of legal assistance and disappearances, can raise a different legal question.

The Iran mission concluded that the scale and organization of the abuses it documented supported the characterization of many violations as crimes against humanity.

The legal importance of that finding is that crimes against humanity generally require more than an isolated unlawful act. The surrounding pattern—such as whether acts formed part of a widespread or systematic attack against a civilian population—is central to the analysis.

The mission’s role is to document and assess that pattern. A court would still have to make its own determination.

What it cannot do: prosecute people

The mission does not have prosecutors with authority to bring criminal charges.

Nor does it have its own police force.

That means the mission cannot simply identify an Iranian official or U.S. commander and order an arrest.

Criminal accountability requires a separate legal mechanism.

One possible route is prosecution by a national court. Depending on domestic law, some countries can prosecute certain international crimes committed abroad under principles commonly associated with universal jurisdiction.

Human Rights Watch notes that war crimes and torture can fall within universal-jurisdiction frameworks in some circumstances, while treaty obligations can require states to prosecute or extradite certain suspects who come within their jurisdiction.

Whether such a case actually proceeds depends on the law of the country concerned, available evidence, the suspect’s presence or accessibility and prosecutorial decisions.

The International Criminal Court is not an automatic answer

The International Criminal Court is sometimes treated as the obvious destination for allegations of war crimes and crimes against humanity.

Its jurisdiction is more complicated.

The United States, Iran and Israel are not parties to the Rome Statute, the treaty establishing the ICC. The Court can nevertheless obtain jurisdiction in certain circumstances, including where the alleged crimes occurred on the territory of a state party, where an accused is a national of a state party, where a non-party accepts the Court’s jurisdiction, or where the UN Security Council refers a situation to the prosecutor.

That means a UN fact-finding report does not automatically send a case to The Hague.

The report and an ICC prosecution are separate processes. Even where jurisdiction exists, prosecutors would need to conduct their own investigation and establish the requirements for a case.

What about the International Court of Justice?

The International Court of Justice is different again.

The ICJ primarily decides disputes between states; it does not function as a criminal court for prosecuting individual soldiers, commanders or political leaders.

This distinction is important when discussing the U.S. allegations. A dispute between Iran and the United States over state responsibility would raise different questions from a prosecution of an individual alleged to have committed a war crime.

The fact-finding mission itself cannot initiate an ICJ case.

A state would need an appropriate jurisdictional basis and would have to bring proceedings through the mechanisms available to the Court.

It cannot force Washington or Tehran to accept its findings

The mission’s conclusions have no automatic enforcement mechanism.

Washington has rejected the latest allegations concerning U.S. military conduct. White House Deputy Press Secretary Anna Kelly dismissed the Human Rights Council’s credibility and argued that Iran was the party responsible for war crimes in the conflict. The Pentagon, meanwhile, has said its own investigation remains ongoing.

Iran also has its own interests in how the findings are received, particularly because the same UN investigation documents serious abuses allegedly committed by Iranian authorities.

This illustrates one of the fundamental limits of international human-rights investigations: documentation and enforcement are different powers.

A mission can produce a detailed record. It cannot compel a sovereign government to acknowledge that record.

It can, however, influence other institutions

The absence of automatic enforcement does not mean a UN report has no consequences.

The findings can be cited by governments during Human Rights Council debates, incorporated into diplomatic discussions, used by civil-society organizations and examined by prosecutors considering national cases.

The Human Rights Council is currently holding its 63rd regular session, and the Iran fact-finding mission’s findings are part of the Council’s September agenda.

The mission has also called for an end to violations, reparations for victims and accountability measures.

Those recommendations are not legally equivalent to a court order. Their impact depends on whether states act on them.

It can recommend reparations—but cannot pay victims

Another important distinction concerns victims.

The mission can document harm and recommend reparations. It cannot itself order Iran or the United States to pay compensation.

Reparations can take different forms, including compensation, rehabilitation, restoration of rights, truth-seeking measures and guarantees that abuses will not be repeated.

The mission’s call for reparations therefore creates a policy and accountability objective, not an immediately enforceable compensation scheme.

For families of people killed or disappeared, that difference can be profound. Establishing the facts may be possible even when obtaining compensation or criminal accountability remains difficult.

It cannot resolve every disputed incident

The mission’s findings should also not be read as a definitive ruling on every allegation made during the war.

Investigators have faced significant access limitations. In the case of the U.S. strikes, they did not receive cooperation from Washington or Israel and instead relied on other evidence.

That means additional evidence could change the picture.

This is particularly important for contested incidents such as the Lamerd strike, where U.S. authorities have disputed responsibility while the UN mission reached a different assessment based on its examination of available evidence.

A responsible reading of the report therefore distinguishes between what investigators found, what governments claim, what independent evidence establishes and what remains unresolved.

The mission’s findings do not make civilian casualties automatically illegal

Another common misunderstanding is that every civilian death in war constitutes a war crime.

International humanitarian law does not work that way.

The legality of an attack can depend on factors including the intended target, whether the target was a legitimate military objective, the information reasonably available to the attacker, precautions taken, proportionality and the attacker’s knowledge or intent.

The UN mission has raised questions about whether sufficient precautions were taken in the strikes it investigated. In separate September findings, it also warned that repeated strikes causing civilian casualties require scrutiny under the rules governing distinction, proportionality and precaution.

The investigative process therefore has to establish more than the existence of civilian casualties.

The same standard applies to allegations against Iran

The principle works in both directions.

The UN mission’s documentation of Iranian killings, torture, arbitrary detention and disappearances does not automatically establish criminal guilt for every official associated with the security apparatus.

Investigators must establish the facts, identify patterns and determine whether the legal elements of particular offenses are satisfied.

Individual responsibility can then become a separate question: who ordered an action, who carried it out, who knew about it and what responsibility did particular officials bear?

That is one reason a fact-finding report can be important without being the final word.

The real value may come years later

The history of international accountability shows why evidence preservation can matter even when immediate prosecutions appear unlikely.

Political circumstances change. Suspects travel. Governments change. National prosecutors acquire new jurisdictional opportunities. International institutions receive new mandates.

A report prepared today can therefore become evidence in a proceeding that does not exist yet.

That is why the Human Rights Council previously instructed the Iran mission to ensure that evidence was fully documented, verified, consolidated and preserved.

The preservation function may ultimately prove more consequential than the immediate political reaction to the report.

What happens next?

The most immediate development is the Human Rights Council’s consideration of the findings during its September session. The Council can debate the report, question investigators and consider further measures, but any subsequent accountability process would require additional legal and political steps.

Beyond Geneva, several developments will matter:

• Further evidence: New military, governmental or independent evidence could strengthen or challenge particular findings.
• Domestic investigations: U.S. or Iranian investigations could provide information unavailable to UN investigators.
• National prosecutions: Prosecutors in countries with relevant jurisdiction could examine individual allegations.
• International proceedings: Where jurisdiction exists, other international mechanisms could potentially use the documented evidence.
• Victim remedies: Governments or courts could eventually consider compensation and other forms of reparation.
• Continued monitoring: Further allegations during the war could expand the evidentiary record.

None of these outcomes is automatic.

The line between investigation and accountability

The most useful way to understand the UN mission is to see it as one part of a larger accountability chain.

Its job is to investigate, document, assess and preserve. It can establish findings that carry international political and evidentiary weight. It cannot arrest suspects, conduct criminal trials, impose sentences or force governments to accept its conclusions.

That limitation does not make the report insignificant. On the contrary, the value of an independent record can increase when governments dispute responsibility and access to evidence is limited. But the report’s ultimate significance will depend on what happens to that record afterward.

The unresolved question is therefore not simply whether the UN has found evidence of war crimes and crimes against humanity. It is whether states, prosecutors and courts with the authority to act will turn that evidence into formal accountability. Until that happens, the fact-finding mission remains what its name suggests: an investigative mechanism whose findings can support future action, but cannot substitute for it.