A large explosion in the Turkish capital, Ankara, has left at least five people killed and 10 injured, the city's governor says. The blast happened next to a passing military vehicle, in an area close to parliament and Turkey's military headquarters. Large plumes of smoke were seen rising from the area and witnesses said the blast was heard all over the city. Deputy Prime Minister Bekir Bozdag called it an "act of terrorism". The Ankara's governor office said the explosion was caused by a vehicle full of explosives that was detonated as military buses were passing by. Ambulances and fire engines were sent to the scene.