The attack, a day after 11 people were killed in a bombing in Istanbul, targeted the police station in the town of Midyat, north of the Syrian border in the mainly Kurdish southeast.
Many ambulances were seen rushing to the scene, reports said.
State-run Anatolia news agency blamed "terrorists" in a reference to militants from the outlawed Kurdistan Workers' Party (PKK).
Tuesday's attack was the fourth on Istanbul this year, dealing another blow to the tourism industry.
Turkey is battling PKK militants, who have killed hundreds of members of the security forces in the southeast.
