A private American aircraft was grounded in Mumbai on Monday evening after it was found overflying Indian airspace without permission.

The Air Traffic Control in Mumbai ordered the pilot of the aircraft, a Boeing 757 owned by the Conco Corporation and registration number N610G, to land at Sahar airport as it did not have 'air defence clearance', Civil Aviation Minister Shahnawaz Hussain told PTI in New Delhi.

The plane was flying from Karachi in Pakistan to Male in the Maldives and landed in Mumbai at 1811 IST.

Airport officials said the American-registered aircraft was taken to an isolated bay for investigation and pilot John Burg and the co-pilot questioned.

In all, there were eleven crew members.

Hussain said the Director General of Civil Aviation and other authorities have been asked to carry out a detailed investigation as the plane was awaiting defence clearance.

The ATC had been informed of the movement of the plane by the military liaison unit.

This is the second intrusion by a foreign aircraft in three days after a US Air Force plane flew 150 nautical miles east of Chennai last Friday.

Customs and immigration officials inspected the cargo plane, sources said.