Iran on Wednesday (08 January) refused to hand over the black box of the crashed Ukrainian plane either to Boeing or the Americans, a decision that could potentially create difficulties for the investigators, reports said.
Iran Civil Aviation Organization chief Ali Abedzadeh said "terrorism" had played no role in the crash, the BBC reported citing Iranian Mehr news agency.
Another official, Qasem Biniaz, blamed an engine fire. "Had the accident happened due to a missile strike, the plane would have exploded in the air," he told the IRNA news agency.
A Kiev-bound Ukrainian Boeing 737 passenger plane with 179 people on board crashed on Wednesday shortly after taking off from the Iranian capital of Tehran, killing all those aboard.
The number of people on board had differed and also the toll was initially said to be 176.
Ukrainian President Volodymyr Zelensky ordered the creation of a crisis team to handle the accident, including top ministers and managed by the country's national security agency.
"We have prepared emergency planes to send to Tehran... to fly out the bodies of the victims, we are waiting a confirmation by Iran for their departure,"
Ukrainian Foreign Minister Vadym Prystaiko said that the victims were 82 Iranians, 63 Canadians, 11 Ukrainians including all the crew, 10 Swedes, four Afghans, three Britons and three Germans.
Ukraine International Airlines has suspended flights to Tehran indefinitely.
(With inputs from IANS)