Updated

Iran's official IRNA news agency is reporting that a helicopter carrying five people has crashed in the Caspian Sea, killing everyone aboard.

The Sunday report quotes Khaleq Sajjadi, an official in the northern Iranian province of Mazandaran, as saying that the helicopter belonging to the National Iranian Oil Company was on a mission to carry an injured person from an oil platform.

IRNA said the crash was caused by a technical malfunction.

Air accidents are not uncommon in Iran, and are believed to be caused by poor maintenance and aging aircraft.