Four suspects have been detained in connection with the attack, Interior Minister İdris Naim Şahin told reporters.
Two terrorists set off a bomb inside their car near a police station at Pınarbaşı in Turkey's central Kayseri province on Friday, killing themselves and one policeman and wounding 18 others.
A statement on a PKK website said Pınarbaşı was the intended target and the bombing was a response to Turkish military attacks, rejecting Turkish media reports that the actual target was in the capital Ankara.
"We have seized four people. Their foreign links have been revealed," Şahin said.
He did not elaborate but broadcaster NTV reported security sources as saying the bombers entered Turkey from neighboring Syria which is in the grip of a the 14-month-old revolt against President Bashar al-Assad.
The Syrian border region is not generally an area of major PKK activity but this month, three Turkish soldiers were killed in clashes with the rebels near the border, a region which has seen thousands of refugees fleeing from the Syrian conflict.
The PKK threatened in March to step up attacks in Turkey if its forces entered Syria after Prime Minister Recep Tayyip Erdoğan, one of Assad's most vocal critics, mooted the possibility of establishing buffer zones within Syria to protect civilians.
The PKK threat signaled a possible renewed alliance with Damascus, which backed the rebels in the 1980s and 1990s.
Şahin said on Friday police followed the car from Göksun district in Kahramanmaraş to Pınarbaşı, about 100 km (60 miles), after it passed a checkpoint in the road without stopping.
Police opened fire as it passed the Pınarbaşı police station and the bomb was detonated. Pınarbaşı is east of Kayseri city, some 325 km (200 miles) southeast of the capital Ankara.
More than 40,000 people have been killed in the PKK insurgency since the group took up arms against the state in 1984. The PKK is listed as a terrorist organization by Turkey, the United States and the European Union.