Ankara: At least 31 people were killed on Friday when two passenger trains collided in Iran's north-central province of Semnan and the death toll is likely to rise, the provincial governor said.

Iranian state television aired footage of four derailed carriages, with two of them on fire. A spokesman for Iran's Red Crescent, Mostafa Mortazavi, told the semi-official Fars news agency that firefighters were trying to control the blaze.

The crash occurred at the Haft-Khan station in the city of Shahroud, about 400 kms (250 miles) east of the capital Tehran.

"The death toll has reached 31 and we are expecting this number to increase," Semnan Governor Mohammad Reza Khabbaz told Fars. Local media have given contradictory casualty tolls. Fars said at least 52 people were hospitalised with injuries.

There was no immediate word on how many passengers were in the trains. But Fars said 100 passengers had been rescued.

Fars said the cause of the crash was under investigation, but it appeared that one of the trains was entering the station had struck another that had stopped.

A local official told state TV that the remote location of the crash had slowed rescue efforts. "So far only one helicopter has reached the scene because of access difficulties," said local Red Crescent chief Hasan Shokrollahi.