DIYARBAKIR, Turkey (Reuters) - Turkish authorities on Saturday detained a key suspect in a bombing that killed seven people and wounded 23 on Thursday in the strife-torn southeast, security sources said.

A member of the police special forces stands next to vehicles, which were damaged by a car bomb attack that targeted a minibus (not pictured) carrying members of the police special forces, occurred in the Kurdish-dominated southeastern city of Diyarbakir, Turkey March 31, 2016. REUTERS/Stringer

Eight members of the security forces were killed on Saturday in separate clashes around the mainly Kurdish region, they also reported.

The outlawed Kurdistan Workers Party (PKK) claimed responsibility for Thursday’s bombing in the city of Diyarbakir, one day before Prime Minister Ahmet Davutoglu visited the city and outlined plans to confiscate and rebuild a historic neighborhood wrecked in fighting since July.

Sources said police apprehended a man they believe parked the bomb-laden car and detonated it when a minibus carrying police officers passed it on a busy street. On Friday, authorities arrested nine people in connection with the bombing.

Six police officers were killed in the town of Nusaybin on the Syrian border on Saturday after suspected PKK militants blew up a building they were searching, security sources said. Four police were being treated for injuries in hospital.

A police officer from a combat unit was also killed in Yuksekova near the Iraqi border, where security forces began operations and imposed a round-the-clock curfew on March 13.

A soldier was killed in the town of Sirnak, the military said on its website.

The predominately Kurdish southeast of Turkey has seen the worst violence in two decades since the PKK abandoned a two-year ceasefire in July and resumed its armed campaign for autonomy. The government says more than 5,000 militants and almost 400 soldiers and police have been killed.

Opposition parties estimate that between 500 and 1,000 civilians have also been killed in the fighting, largely concentrated in densely populated urban centers.

Late on Friday, militants used a car bomb to strike a military outpost near the town of Kiziltepe by the Syrian frontier. One civilian was killed and 13 people wounded, including three children and two soldiers.