Iran has admitted "unintentionally" shooting down a Ukrainian passenger jet, killing all 176 people on board.
An investigation found that "missiles fired due to human error", President Hassan Rouhani said. He described the crash as an "unforgivable mistake".
The military said the jet turned towards a sensitive site belonging to Iran's Revolutionary Guards and was then mistaken for a cruise missile.
Iran had previously rejected suggestions that it was to blame.
The downing of Ukraine International Airlines flight PS752 on Wednesday came just hours after Iran carried out missile strikes on two airbases housing US forces in Iraq.
The strikes were a response to the killing of senior Iranian commander Qasem Soleimani in a US drone strike in Baghdad on 3 January.