A strike on an Iranian girls' school that killed 165 schoolgirls may be the result of US use of outdated targeting data, news agency Reuters reported, citing two sources familiar with the matter on Wednesday. The report provides new details about what would rank among the worst cases of civilian casualties in decades of US conflicts.

The majority of those killed in the strikes were girls between the ages of 7 and 12 years old. Neither the United States nor the Israeli Government has yet taken responsibility for this attack.

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The report came in the midst of an internal US military investigation that showed US forces were likely responsible for the strike on the girls' school in Minab. Video surfaced that experts say appears to show a US Tomahawk missile striking the area. But exactly how the tragedy unfolded has remained unclear, and the Pentagon has declined to comment, saying the investigation remains ongoing.

I don't know: Trump on Iran school bombing

When asked by reporters, US President Donald Trump said he was unaware of the investigation outcome.

The strike during the first day of US and Israeli attacks on Iran killed 165 students, according to Iran's ambassador to the UN in Geneva, Ali Bahreini. According to archived copies of the school's official website, the school is adjacent to a compound operated by the Islamic Revolutionary Guard Corps, the military force that reports to Iran's supreme leader.

Outdated data used: Reports

The news agency, in its report, claimed one of the sources who spoke on the condition of anonymity said officials responsible for creating targeting packages appeared to have used out-of-date intelligence. The second source told Reuters that out-of-date intelligence appears to have been used. In response to a request for comment, the Pentagon said that the incident is under investigation.

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The possible use of outdated targeting data was first reported by the New York Times earlier on Wednesday. It is unclear how old data ended up being used for the strike, and what, if any other factors, might be responsible for the error. The investigation is still ongoing, and it is not clear when a final conclusion will be reached.

US Defence Secretary Pete Hegseth responds

US Defence Secretary Pete Hegseth and other US officials have stressed that the United States would not deliberately target civilians. Deliberately attacking a school, hospital, or any other civilian structure would likely be a war crime under international humanitarian law. Images of the girl's funeral were shown on Iranian state television last week.

(CREDIT: REUTERS)

Their small coffins were draped with Iranian flags and passed from a truck across a large crowd towards the grave site. The chilling video and photographs went viral quickly on the internet. This triggered a massive backlash from the Trump administration. However, amid the uncertainty over the spiralling situation, it is unlikely that Trump would stop the war amid pressure.

(With inputs from agency)