Police Chief Mustafa Calıskan has ordered that any helicopters present in Istanbul airspace without official permission from the authorities be shot down.
Reinforced police squads are patrolling the streets.
The report comes as on Saturday an attempted military coup has gripped the country to overthrow President Recep Tayyip Erdogan.
The coup was however repelled in which a total of 265 people were killed, scores wounded and nearly 6,000 arrested.