Iran’s military says it “unintentionally” shot down a Ukrainian passenger jet, Iran’s state TV reports.
The statement said it had done so due to “human error” after the plane flew close to a sensitive site belonging to Iran’s Revolutionary Guards.
Those responsible would be held accountable, the statement said.
Iran had previously rejected suggestions that one of its missiles brought down the plane near the capital, Tehran, on Wednesday.
But pressure mounted after the US and Canada, citing intelligence, said they believed Iran had brought the plane down with a missile, possibly accidently.
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.
The Ukrainian flight was headed to the Canadian city of Toronto via the Ukrainian capital, Kyiv.
US media have speculated that the airliner may have been mistaken for a warplane as Iran prepared for possible US retaliation.
Iran has promised a full investigation. However, TV images from the crash site on Thursday showed a mechanical digger helping to clear debris away, raising concerns that important evidence could have been removed.