The Turkish military opened fire on civilians gathering on Istanbul's Bosporus Bridge, reports and footage on Twitter shows.
Seventeen Turkish police officers were also reportedly killed in an helicopter attack on a special police headquarters on the outskirts of Ankara, according to AP.
Tanks are reported to be firing around the Turkish parliament building, according to Press TV.
The state-run Anadolu Agency also reports that military helicopters fired at the National Intelligence Agency HQ.
Police and the military have also reportedly fired at each other in the Kizalay area of central Ankara.
The military earlier said in a statement it was taking control of the government in order to return it to democracy. President Tayyip Erdogan and government officials have said the coup lacks broad support within the military. Erdogan has called on his supporters to take to the streets in defiance.