Iran said it could take one or two months to extract information from the voice and flight data recorders.
DUBAI - Iran said on Friday it wanted to download black box recordings itself from a Ukrainian airliner that crashed after Canada and others said the plane was brought down by an Iranian missile, probably by mistake.
Iran, which has denied the Boeing 737-800 was downed by a missile, said it could take one or two months to extract information from the voice and flight data recorders. It said it could ask Russia, Canada, France or Ukraine if it needed help.
Tehran also said the probe might take one or two years.
Ukrainian President Volodymyr Zelenskiy said he could not rule out a missile strike but this had not been confirmed. Kiev has said its investigators wanted to search the crash site for any debris of a Russian-made missile used by Iran.
The Ukraine International Airlines flight to Kiev from Tehran crashed on Wednesday when Iran was on alert for a US military response hours after firing missiles at US targets in Iraq.
On social media, many Iranians expressed anger that the plane was allowed to take off and voiced worries as images, which could not be independently verified, circulated on Twitter suggesting the crash site had been cleared by bulldozers.
"We prefer to download the black boxes in Iran. But if we see that we can't do that because the boxes are damaged, then we will seek help," Ali Abedzadeh, head of Iran's Civil Aviation Organisation, told a news conference in Tehran.
State television earlier showed the battered black boxes, saying their information could be downloaded and analysed.
Canadian Prime Minister Justin Trudeau, citing intelligence from Canada and other sources, has blamed an Iranian missile for bringing down the plane that had 63 Canadians on board, although he said it "may well have been unintentional".
"The evidence indicates that the plane was shot down by an Iranian surface-to-air missile," he said.
Ukraine's general prosecutor asked Canada "to provide information available to the Canadian side that may facilitate criminal investigations" into the crash.
Russia's deputy foreign minister said Moscow saw no grounds to blame Iran for the crash, TASS news agency reported.