At least four police officers have been killed and 14 others injured in a bomb attack in Turkey's Kurdish-majority city of Diyarbakir, government officials said.
The private Dogan news agency said a car bomb targeted a bus transporting police.
The agency blamed "terrorists" for the blast, using the government designation for Kurdish rebels.
Diyarbakir has been hit by waves of violence in fighting between the banned Kurdistan Workers Party (PKK) and the government.
Last week, the PKK claimed responsibility for a bombing that killed at least three security force members and wounded 24 at a military outpost near Diyarbakir.
Ankara says some 300 members of the security forces had been killed since the conflict flared up in 2015.
The PKK resumed its more than three-decade insurgency after a fragile truce collapsed last summer.
Over 40,000 people have been killed in the conflict since the PKK took up arms in 1984 demanding Kurdish autonomy.