A UN inquiry has started investigating a fatal strike on a primary school that killed 168 children on the first day of US-Israeli attacks on Iran, one of its members told reporters, Reuters reports.

“We’re at an early stage of that investigation,” Max du Plessis, a member of the UN Fact-Finding Mission on Iran, told a Geneva press conference, saying that it had credible reports backing Iran’s death toll.

“It’s clear to us that whatever happens in respect of such an event, given the innocent lives that have been lost, there is a critical need for such an investigation to be done and for an independent outcome to follow,” he said.

Reuters reported on March 5 that US military investigators believe it is likely that US forces were responsible but have not yet reached a final conclusion or completed their investigation. The Pentagon has since elevated the probe.