Gunmen on Wednesday attacked a police car escorting a bus that had previously carried the Turkish prime minister to an election event, leaving one officer dead and another injured, Turkish media reported.
The unidentified attackers opened fire with automatic weapons and threw hand grenades at the vehicle after the entourage left the northern city of Kastamonu following an election rally for the governing Justice and Development (AK) Party, according to the state- run Anatolia News Agency, DPA reported.
Prime Minister Recep Tayyip Erdogan was not on the bus, having left the rally earlier by helicopter.
One policeman was killed as the gunmen attacked. The other took shelter in the bus, Anatolia reported.
Security forces counter-attacked, but the assailants fled the scene. Military teams are now hunting them, Anatolia reported.
Erdogan condemned the attack, apparently blaming Kurdish separatists.
"Those dark minds, these terrorists, these separatists are only able to do this, those who understand there is nothing they can do through the ballot box," he said at a rally in Amasya soon afterwards
The separatists rebel group the Kurdistan Workers' Party has been fighting a three-decade insurgency against the Turkish state.
Turkey is preparing for general elections on June 12.