The pilots aboard the Ukraine International Airlines passenger jet that became a fireball in mid-air and crashed in Iran, killing 176 people, were dead before the plane hit the ground, officials say.

The Boeing 737-800 was hit by a missile directly beneath the cockpit after taking off from Tehran’s Imam Khomeini International Airport on Wednesday, Ukraine’s top security official says.

The Kiev-bound flight exploded and crashed hours after Tehran launched missiles at US bases in Iraq in response to the assassination of top Iranian general Qasem Soleimani.

“The photo shows the part where the missile hit,” Oleskiy Danilov told the BBC, referring to a photograph of what remains of the nose of the plane.

The bottom half of the cockpit is missing.

“It hit the cockpit from underneath. We think this is proof. And it explains why we didn’t hear anything from the pilots. They died immediately after the first hit.

“As soon as the Iranians gave us access to these items, our specialists kept us updated every hour as to what was happening. And very quickly as we gathered information, we understood what had happened,” he said.

Iran has taken responsibility for shooting down the aircraft, which had 57 Canadians on board. After initial denials, Tehran admitted it had unintentionally downed the Ukrainian jet.

President Hassan Rouhani said a military probe into the tragedy had found “missiles fired due to human error” brought down the Boeing 737, calling it an “unforgivable mistake.”

Other pictures shared by the Ukrainian official show parts of the plane scattered over vast distances.

The crash has raised alert levels in Iran and forced international airlines to divert away from airspace over Iran.

In Tehran, tensions remain high. Britain’s ambassador to Tehran was arrested on Saturday after attending a vigil to honour those killed in the crash.

Iran’s Mehr news agency said the ambassador, Rob Macaire, was arrested for his alleged “involvement in provoking suspicious acts” at the gathering in front of a local university.

“Can confirm I wasn’t taking part in any demonstrations,” Macaire wrote on Twitter.

“Went to an event advertised as a vigil for victims of #PS752 tragedy.”

Iran’s Supreme Leader Ayatollah Ali Khamenei also offered his condolences and ordered the armed forces to address “shortcomings” so that such a disaster does not happen again.

with AFP