Iran has again rejected suggestions that one of its missiles brought down a Ukrainian passenger jet near the capital, Tehran, on Wednesday.
Its civil aviation chief said on Friday he was “certain” that the plane was not hit by a missile.
He was responding to claims by Western leaders that evidence suggested the plane had been hit by a surface-to-air missile, possibly in error.
The crash of Ukraine International Airlines flight PS752 with the loss of 176 lives came just hours after Iran carried out missile strikes on two airbases housing US forces in Iraq.
US media have speculated that the airliner may have been mistaken for a warplane as Iran prepared for possible US retaliation.
Victims of the crash included 82 Iranians, 63 Canadians, and 11 Ukrainians as well as nationals from Sweden, the UK, Afghanistan, and Germany.
Meanwhile, the “black box” flight recorders recovered from the wreckage will be opened on Friday, Iran’s official Irna news agency reported.
What does Iran say?
At a news conference on Friday, Iran’s Civil Aviation Organisation (CAOI) chief Ali Abedzadeh repeated his view that a missile was not the cause of the crash.
“The thing that is clear to us and that we can say with certainty is that this plane was not hit by a missile,” he told reporters.
“As I said last night, this plane for more than one and a half minutes was on fire and was in the air, and the location shows that the pilot was attempting to return.”
On Thursday, government spokesman Ali Rabiei accused the US and its allies of “lying and engaging in psychological warfare” in their speculation over the cause of the accident.
An Iranian official said on Friday that there was documentation to prove that the plane had a mechanical issue before take-off. It was not signed off for flying, but Ukrainian airline officials had overruled these objections, the official said, without giving further details.
What has been said about a possible missile strike?
Canadian Prime Minister Justin Trudeau said he had received intelligence from multiple sources indicating the plane was shot down by an Iranian surface-to-air missile, adding that it was possible that this was unintentional.
But he said it was too early to apportion blame or draw any conclusions, and refused to go into detail about the evidence.
The Ukrainian flight was headed to the Canadian city of Toronto via the Ukrainian capital, Kyiv.
The US National Transportation Safety Board (NTSB) confirmed it had been invited to take part in the investigation and would send a representative.
Boeing said it would support the NTSB in the inquiry, and the Transportation Safety Board of Canada said it had also been invited to the accident site by Tehran.
France’s BEA air accident agency said on Friday it had also been invited to take part in the investigation.