Turkey's intelligence agency headquarters were attacked by military helicopters and heavy machinegun fire during an attempted military coup overnight, wounding at least three people, an intelligence source told Reuters on Saturday.

The head of the agency, Hakan Fidan, was at a secure location throughout the events and was in constant contact with President Tayyip Erdogan and Prime Minister Binali Yildirim, the source said.

The intelligence agency was still working with the armed forces, the police and the government against the coup plotters in ongoing operations in Istanbul and Ankara in particular, the source said.