Eight people have been arrested over a car bomb attack in Istanbul's Sancaktepe neighbourhood, broadcaster NTV said, adding that the suspects included a person believed to have left the explosives-laden car at the scene.
Six soldiers and a civilian were wounded when the car blew up near a military base in Turkey's biggest city on Thursday, the latest in a spate of bombings this year.
In a separate development, at least eight Turkish soldiers and 21 fighters from the outlawed Kurdistan Workers' Party (PKK) were killed on Friday, according to the military and media reports, as violence in the largely Kurdish southeast widened a day after two bombings.
After the collapse of a ceasefire between the PKK and the government last July, Turkey's southeast has seen some of its worst violence since the height of a Kurdish insurgency in the 1990s.
Six soldiers were killed and eight wounded in clashes with PKK fighters in the southeastern Hakkari province, the army said in a statement.
Two more soldiers were killed in a separate incident when a military helicopter crashed in Hakkari due to a technical fault, the military said. Six PKK fighters were also killed in an operation in that region, it said.
READ MORE: Deadly car bomb hits Turkey's Diyarbakir
At least 15 PKK fighters were killed in clashes in Sirnak province, NTV reported, citing the Turkish military.
On Thursday, four suspected bomb-makers were killed and 17 people wounded when an explosion ripped through Diyarbakir, a village in the southeast, as PKK fighters loaded explosives on to a small truck, the government said.
That blast was just hours after the car bomb in Istanbul.
No one has claimed responsibility for the attack.
Turkey has suffered a series of bombings this year, including two suicide attacks in tourist areas of Istanbul blamed on Islamic State of Iraq and the Levant (ISIL) and two car bombings in the capital, Ankara, which were claimed by a PKK offshoot.