A plane that crashed in Iran with 176 people on board was trying to return to the airport when it crashed, Iranian investigators have said.

The Boeing 737-800 went down just minutes after taking off from Tehran's airport, leaving no survivors.

An initial probe found the aircraft experienced a problem as it was leaving the airport zone, and was "on fire".

The crash came just hours after Iran carried out missile strikes on two air bases housing US forces in Iraq.

However there is no evidence the two events are linked.

On Thursday, Oleksiy Danylov, the secretary of Ukraine's security council, said investigators wanted to search for possible debris from a missile at the site of the crash. Iran is known to have Russian missile defence systems.

BBC