A preliminary US military investigation has reportedly determined that Washington was responsible for a deadly Tomahawk missile strike on an Iranian elementary school in February that killed scores of children.

According to the New York Times, quoting unnamed US officials and others familiar with the initial findings, the investigation has concluded that the strike on 28 February on the Shajarah Tayyebeh elementary school building was the result of a targeting mistake by the US military planners.

Iranian officials had put put death toll from the attack as at least 175 people, the majority of them children, in one of the worst and most shocking American strikes producing civilian fatalities in recent memory.

The findings appear to confirm assertions by Tehran which had produced video footage of the US missile strike and fragments of US-made missile parts, despite Donald Trump’s efforts to suggest Iran had hit the building.

According to the report, the inquiry – which has yet to be completed – has found that officers at US Central Command created the target coordinates for the strike using outdated data provided by the Defense Intelligence Agency.

While independent analysis of the strike had pointed strongly to US culpability, the Trump administration has continued with a policy of evasion around the attack that hit the school in the town of Minab close to buildings used by Iran’s Islamic Revolutionary Guards naval forces.

On Saturday, the US president, Donald Trump, declared that Iran was responsible for the school bombing. “In my opinion, based on what I’ve seen, that was done by Iran … they’re very inaccurate, as you know, with their munitions. They have no accuracy whatsoever. It was done by Iran.” The president presented no evidence for his claim.

His assertion has not been repeated by spokespeople for the US military, who have said only that they are “investigating” the bombing.

But the Trump administration’s efforts to avoid responsibility for the horrific attack continued on Wednesday with Karoline Leavitt, the White House press secretary, saying in a statement: “As the New York Times acknowledges in its own reporting, the investigation is still ongoing.”

Historic satellite imagery shows that while the school’s building was once part of the wider IRGC complex, it has been walled off from the barracks for at least nine years. It has had clear visual indications that it is an educational facility, including colourful murals on the walls and small sports playing fields – both visible in some satellite imagery.

There is no indication that the school was a military-use building at the time of the strike. Its location, however, provides a plausible reason why the US or Israel may have selected targets in that area.

A number of videos of the bombed school, which have been verified by the Guardian, were shared on Iranian social media after the explosion.

At least four show what is clearly the same site from different angles and approaches, with shared motifs such as the school’s distinctive, colourful murals.

One of those videos shows the rubble of the destroyed school and pans to show thick smoke rising over the fence – from the direction of the IRGC base. The video was one of the first indications that the bomb that hit the school was one of a series of strikes that also targeted the IRGC complex next to it.

On 8 March, Iranian state media Mehr News Agency released a video of a missile hitting a location in Minab. The video was geolocated by the investigative collective Bellingcat. Geolocation is the process of cross-referencing physical features shown in an image or video (such as buildings, billboards, signage or mountains) with verified images of a site, such as satellite images, to confirm where it was captured.

Bellingcat was able to match buildings, water towers, trees and roads from the video with satellite images of the Minab site, to locate what angle it was filmed from and where the missile landed. It determined that the missile had struck the IRGC compound next to the school.

The missile shown in the video has been identified by munitions experts as a Tomahawk missile.

“Given the belligerents, that indicates it is a US strike, as Israel is not known to possess Tomahawk missiles,” said NR Jenzen-Jones, the director of Armament Research Services, an intelligence consultancy that provides munitions analysis to governments and NGOs. The US is the only country involved in the Iran war to have this weapon.

He added: “Despite various claims circulating online, the munition in question is clearly not an Iranian Soumar missile: the Soumar has a distinctive external engine located towards the rear, on the underside of the munition.”