A large explosion has rocked the Turkish city of Tunceli, killing seven people, mainly security personnel.
The blast targeted a vehicle carrying security forces.
The city is near the country's Kurdish area and suspicion will automatically fall upon Kurdish rebel group the PKK, says the BBC's Istanbul correspondent James Reynolds.
Fighting between Turkish troops and the PKK - the Kurdistan Workers' Party - has escalated in recent months.
Six members of the security forces and one civilian died in the attack in the Ataturk neighbourhood, said local media and hospital sources.
Turkish TV stations showed pictures of workers trying to put out fires in two burnt-out vehicles.
Reports said a vehicle carrying explosives was remotely detonated as an armoured vehicle carrying security forces passed by, sending a huge plume of dark smoke over the city.
Some reports said a civilian vehicle was also damaged in the explosion.
One report, in Turkey's Hurriyet Daily News, said security forces arriving on the scene clashed with suspected PKK militants, with one militant killed.
No-one has yet said they carried out the attack, but Kurdish rebels are active in the city, which is the capital of the province of Tunceli.
This incident comes amid a surge in fighting in the three-decade conflict between the military and the PKK which in total has killed more than 40,000 people.
In mid-September, Prime Minister Recep Tayyip Erdogan said 500 Kurdish rebels had been "rendered ineffective" by Turkish forces in the space of a month.
Many have died in Turkish aerial campaigns against suspected PKK hideouts in the south-east of the country.
PKK fighters killed 17 Turkish soldiers and injured scores over three days in Bingol province last week.
Earlier this month, one soldier and three Kurdish militants were killed when insurgents attacked army outposts in Tunceli.
This has become the most violent period in fighting with the Kurds since the capture of the PKK's leader, Abdullah Ocalan, in 1999, our correspondent says.