Iran initially denied it brought down the aircraft in the tense aftermath of Iranian missile strikes on US targets in Iraq, which came after the killing, by a US drone, of Iran General Qassem Soleimani.

"The Islamic Republic of Iran deeply regrets this disastrous mistake," Iranian President Hassan Rouhani wrote on Twitter, promising those behind the incident would be prosecuted. "My thoughts and prayers go to all the mourning families," he added.

Iran’s Foreign Minister Mohammad Javad Zarif also commented on Twitter. "Human error at time of crisis caused by U.S. adventurism led to disaster." He was citing an initial armed forces investigation into the crash of the Boeing 737-800.

An Iranian military statement, the first to indicate Iran’s shift in position, said the plane had flown close to a sensitive military site belonging to the elite Revolutionary Guards.