Military officials said the dead were security guards

The train was carrying 45 passengers between the towns of Elazig and Tatvan in Bingol province.

The bomb was placed on the track and derailed some of the carriages. Another train sent to the rescue was also attacked, said the provincial governor.

There are no reported casualties from the second attack. Officials blamed Kurdish paramilitaries of the PKK.

Military officials said those killed were security guards.

Second explosives

Turkish president Ahmet Necdet has sent a message of condolence to the families of those killed.

Some people were trapped under the derailed cars near the town of Genc, said governor Ozgur Korukcu, according to Anatolia news agency.

Reports said a second set of explosives was found and defused 500 metres down the track.

The second train was attacked and blocked about 1km from the first but there are no further reports on its fate.

In another incident in south-eastern Turkey, three police officers were injured by a bomb while investigating a suspicious package in the city of Diyarbakir.

The BBC's Jonny Dymond in Istanbul says Bingol has always been a difficult place for the authorities to control but the attack on the train is a blow to the security forces.

The PKK, he says, remains a great threat after lifting its ceasefire more than a year ago.

More than 35,000 people have died in the PKK's armed campaign for self-rule in south-east Turkey that began in 1984.