In a rural area in the northeastern province of Gumushane, PKK members ambushed a military vehicle, which overturned after the driver was wounded and lost control, Governor Veysel Dalmaz told the Anatolia news agency.

Four soldiers were killed and three others injured in the incident, he said.

A local security official contacted by AFP said the PKK, blacklisted as a terrorist group by Ankara and much of the international community, was behind the attack.

It was not immediately clear how many of the soldiers were killed by gunfire or as a result of the vehicle overturning, he added.

Gumushane is not a region where the PKK is usually active, but following several attacks there last year officials said the group was seeking to establish itself in the area.

Earlier Sunday, a landmine exploded while a freight train was passing in the mainly Kurdish southeast, injuring four train security guards.

The landmine was planted on rail track that links the provinces of Bingol and Elazig and was activated by remote control.

Officials said they believe the blast was the work of the PKK, blamed for similar train attacks in the past.

Last year, five railway security guards were killed when a bomb ripped through a train, also in Bingol.

At least 94 PKK militants and 62 members of the security forces have been killed in mounting unrest this year, according to an AFP count.

Kurdish militants have also claimed responsibility for 13 bomb blasts in urban centers across the country, in which nine people were killed and more than 150 others injured.

The Kurdish conflict in Turkey has claimed more than 37,000 lives since 1984 when the PKK took up arms for Kurdish self-rule in the southeast.