Iranian President Masoud Pezeshkian said he will use his General Assembly address to highlight the deaths of dozens of children in a strike on an elementary school in southern Iran at the outset of the war.

Here’s a recap of what happened:

On February 28, at the start of the US-Iran war, the US struck the Shajareh Tayyiba school in Minab, southern Iran, while the US military was attacking a neighboring Islamic Revolutionary Guard Corps facility, CNN has reported. At least 156 people, including 120 children and 26 teachers, were killed, according to Iranian officials.

The strike was considered one of the worst civilian casualty incidents in recent US military history.

In March, two sources briefed on the preliminary findings of an ongoing internal investigation told CNN that US Central Command created target coordinates for the strike that hit the school using outdated information provided by the Defense Intelligence Agency, which contributed to the mistake.

US President Donald Trump had initially asserted that Iran might be to blame for the strike, though when pressed on why no one in his own administration seemed to be publicly supporting that claim, he responded: “Because I just don’t know enough about it.”

The Pentagon’s internal investigation remains stuck in limbo, as the stage where Defense Intelligence Agency analysts review satellite imagery and other intelligence sources has not yet been ordered by the Pentagon, three sources familiar with the matter told CNN in July.

This month, a United Nations fact-finding mission concluded in a new report that the strike may have been a war crime. The findings by the UN’s Independent International Fact-Finding Mission still need to be presented to the UN Human Rights Council, but could later be used by international courts like the International Criminal Court.