100+ International Law Experts Say US Strikes on Iran Violate UN Charter, Could Be War Crimes

A day after President Donald Trump threatened to bomb Iran "back to the Stone Age" during a primetime speech, a group of more than 100 international law experts said US strikes over the past month of war clearly violated the United Nations Charter and may amount to war crimes.

On Thursday, Just Security released a letter signed by senior professors, law association leaders, former government advisers, military law experts, and former judge advocates general (JAGs) arguing that the US has violated international law both by launching the war alongside Israel on February 28 and through its conduct while prosecuting it since then.

"The initiation of the campaign was a clear violation of the United Nations Charter," the experts said, "and the conduct of United States forces since, as well as statements made by senior government officials, raise serious concerns about violations of international human rights law and international humanitarian law, including potential war crimes."

The charter allows for the use of military force against other nations only in self-defense against an imminent armed attack or when authorized by the UN Security Council.

"The Security Council did not authorize the attack. Iran did not attack Israel or the United States," the experts said. "Despite the Trump administration’s varied and sometimes conflicting claims to the contrary, there is no evidence that Iran posed an imminent threat that could ground a self-defense claim."

They highlighted statements from administration officials, such as Defense Secretary Pete Hegseth, who has described the rules of military engagement as "stupid" and said the US was seeking to prioritize "maximum lethality, not tepid legality."

They also mentioned the defense secretary’s pledge to give “no quarter, no mercy for our enemies” in mid-March—noting that the threat is not only “especially prohibited” under international law, but also the Department of Defense’s own war manual.

Trump himself has said explicitly that he doesn't "need international law" and suggested that the US was conducting strikes against certain Iranian infrastructure, including an oil hub, "just for fun."

This has culminated in what the experts say have been widespread violations of the laws of armed conflict, including rampant strikes against civilians and political leaders with no military role, as well as critical infrastructure like oil and other energy facilities, which the UN's high commissioner for human rights, Volker Türk, condemned last month for their “disastrous” impacts on civilians.

They also raised serious concerns about attacks on schools, health facilities, and homes, citing recent data from the Iranian Red Crescent, which found that at least 67,414 civilian sites have been struck, including 498 schools and 236 health facilities.

According to a report on Wednesday from the Human Rights Activists News Agency (HRANA), a US-based human rights monitor for Iran, more than 1,600 civilians have been killed since the war began on February 28, including 244 children.

The experts raised particular concern about the US bombing of the Shajareh Tayyebeh Primary School in Minab on the first day of the war, which killed at least 175 people, most of whom were children aged 7-12.

"The strike likely violates international humanitarian law, and if evidence is found that those responsible were reckless, it could also be a war crime," they said. "The strike is among the deadliest single attacks by the US military on civilians in recent decades."

They warned that a lack of accountability has only allowed the administration's conduct to grow more aggressive and reckless, with Trump issuing increasingly bombastic threats, including to "obliterate” Iran's power plants and water facilities and "do things that would be so bad they could literally never rebuild as a nation again.”

They also called out Hegseth's dismantling of internal safeguards meant to prevent the military from violating international law, including the removal of senior lawyers from oversight positions and the elimination of "civilian environment teams" meant to help the military understand how their operations could impact the population.

While the letter focused on violations by the US government, it also said Iran's government has committed illegal actions during the conflict, by continuing its violent crackdowns against protesters and by conducting strikes on civilian areas in Israel and the Gulf states in retaliation for the war.

The experts urged US officials to uphold international law and reminded other nations "of their legal obligations not to aid or assist the United States, Israel, or Iran in the commission of internationally wrongful acts."

The legal scholars who signed the letter joined a growing chorus of international law experts and human rights organizations that have condemned the war as illegal, including multiple UN bodies, Human Rights Watch, Amnesty International, and Human Rights First.

One of the letter's signatories, American University law professor Rebecca Hamilton, said she hoped the letter would spur action from "those with constitutional responsibilities," including the US Congress, which she said was "flailing in the face of illegal actions by the executive."

Hamilton said she was "proud to be part of this professional community, willing to come together to give voice to the rule of law."