A police compound in the Turkish capital Ankara was struck by three rockets on Friday, Interior Minister Muammer Guler said.
Two buildings belonging to the national police directorate in the district of Dikmen were hit, but no one was hurt, Guler said. A third rocket fell into the grounds.
Dikmen is one of the places across Turkey where anti-government protests have flared in recent months.
The television station NTV said it was not yet known who was behind the attack. Guler said police had found a rocket launcher and material belonging to "an illegal organisation" near the scene of the attack.
Left-wing radicals, Islamist extremists and Kurdish militants have all staged attacks in Turkish cities in the past.
The far-left Revolutionary People's Liberation Party-Front (DHKP-C) in February claimed responsibility for a suicide bombing at the U.S. Embassy in Ankara that killed a security guard.
Turkey blamed groups linked with the Syrian government for a car bombing in May in the town of Reyhanli, near the Syrian border, that killed more than 50 people. As civil war rages in Turkey's neighbour, Prime Minister Tayyip Erdogan has repeatedly called for Syrian President Bashar al-Assad to step down.