A UN fact-finding mission on Iran has said there are reasonable grounds to believe the US was behind two military strikes on a school and sports facility in Iran in ⁠February, and that these constituted war ⁠crimes.

It also found Iranian ​authorities committed crimes against humanity during their deadly crackdown on anti-government protests.

The findings by the independent international fact-finding mission on Iran, to be submitted to the UN human rights council in Geneva, examined the ⁠US’s conduct during the Iran war that began in February and the Iranian government’s response to nationwide unrest that begun in late December.

US officials have previously said military ⁠operations are conducted in accordance with the law of armed conflict, while Iran has consistently rejected allegations of systematic rights violations.

The UN experts said they found ​reasonable grounds to believe US forces were responsible for an attack on the ‌Shajareh Tayyebeh primary school in the city of ‌Minab, where more than 150 people were killed, including around 120 schoolchildren, according to Iranian officials.

It constituted an indiscriminate attack causing civilian deaths and damage to ‌civilian infrastructure, amounting to a war crime under international law, the mission concluded.

According to the report, the US relied on intelligence suggesting a senior Iranian military commander was present at the site but failed to adequately verify the information before launching the strike. Investigators said the failure to update targeting intelligence and confirm the building was a military objective amounted to more than mere negligence.

“Rather, the US directed the strikes at the building of the school while being aware of a substantial risk of striking a civilian object and acting recklessly as regards the possibility that this would happen.”

In June the US president, Donald Trump, said ‌that “nobody” purposefully attacked a girls’ school in Iran in February, citing an investigation into the incident. Reuters first reported that an initial internal US military investigation showed US forces were probably responsible for the fatal strike in Minab in southern Iran.

The Pentagon has since elevated ​the inquiry but it has not published any preliminary findings.

UN experts said the school was a clearly identifiable civilian object and found no evidence it was being used for military purposes.

The experts reached a similar conclusion over a strike on a sports centre in Lamerd. The report said the attack damaged nearby residential buildings and a school and killed and injured 22 civilians. It concluded that the strike was indiscriminate and therefore constituted a war crime.

US Central Command said in a statement in March that ⁠US forces did not launch any strikes into the city of Lamerd on that day.

The UN mission found ​that the Iranian authorities carried out a widespread and systematic ​attack against civilians during protests that erupted in late ​December last year, involving unlawful killings, torture, arbitrary detention, enforced disappearances and severe restrictions on freedom of expression.

Rights groups say bystanders were among ​those killed during the biggest crackdown ‌since Shia Muslim clerics took ​power in the 1979 revolution. Tehran blamed “terrorists ​and rioters” backed by exiled opponents and foreign foes the US and Israel.

The investigation said it could not independently verify the death toll, but that it believed the number of dead and injured was probably far higher than official figures, which say 3,038 people were killed and 25,000 people injured.

The government’s response to the protests, including violence and killings, cutting off the internet and use of the death penalty, marked a significant escalation from previous patterns of suppressing dissent, the report said.