An Indigo [Images] aircraft flight E-664 made an emergency landing at New Delhi [Images] airport. The National Security Guard and Delhi police's quick response team have been called in. The Border Security Force's planes have been put on standby. The plane has been isolated at the airport. No one  has disembarked from the aircraft.

The possibility of a hijack has not been ruled out.

Senior intelligence bureau officials have debunked the theory that Indigo flight has been hijacked. Major television networks have been highlighting the so-called hijack incident. NDTV has called the whole episode as a 'mock exercise'.

"One foolish pilot passed on a message that the plane had been hijacked. Later on he changed his statement and said that it was a rowdy passenger onboard who was creating a ruckus," a top ranking IB officer told rediff.com.

The aircraft has been parked at an isolation bay which is far away from the main run ways. The NSG and CISF would inspect the aircraft, sources said.

When called Delhi police PRO Rajan Bhagat said that they have no information on the hijack incident. Indigo airlines has issued a statement saying that no passengers were harmed.

Last week Mumbai [Images] police had been tipped off a possible hijack by union home ministry. Later the ministry withdrew the advisory.