The blast occurred when the train carrying both passengers and goods ran over a mine planted on the tracks in Bingol province by the "terrorist organization", the agency said, using the official jargon for the outlawed Kurdistan Workers' Party (PKK).

The explosion derailed five of the train's 33 wagons, but not the passenger cars, Mehmet Habib Soluk, the undersecretary of the transport ministry, told the agency.

The 55 passengers and the 11 crew on the train were safe, he added.

Authorities have blamed the PKK, which has been fighting the Ankara government for more than 20 years, for similar attacks in the past.

In 2005, five railway security guards were killed when a bomb belived to have been planted by Kurdish rebels ripped through a train in Bingol.

Since December, Turkey has stepped up military action against the PKK, carrying out air strikes plus a week-long ground incursion in February into northern Iraq, where it says more than 2,000 PKK rebels have taken refuge.

The PKK, which is listed as a terrorist group by Turkey and several Western countries, has been fighting for self-rule in Turkey's mainly Kurdish southeast since 1984. The conflict has claimed more than 37,000 lives.