An explosion and gunshots were heard on Wednesday at Turkish Aerospace Industries’ facilities in Ankara's Kahramankazan district.
HaberTurk television said the explosion may have been caused by a suicide bomber.
Security forces, ambulances and firefighters were dispatched to the site, NTV television reported.
Employees at the company, located in the outskirts of Ankara, were taken to a safe area, the report said.
According to the latest reports, 4 were killed and 14 others were injured in the attack.
MNA