A reported plane hijacking from Bombay to New Delhi was a false alarm, the Indian Government says.
It says it was caused by an anonymous phone call and confusion in the cabin and cockpit.
An anonymous phone call to an air traffic control station set off the chain of events, Civil Aviation Minister Shahnawaz Hussain told reporters.
He said the pilot, Capt Ashwini Behl, was told about the phone call and sealed his cockpit door.
The pilot thought the hijackers were among the passengers and the passengers thought the hijackers were in the cockpit, he said.
There was also confusion, Mr Hussain said, because one of the passengers did try to enter the cockpit, saying he was some sort of official. But he did not have proper identification.
Mr Hussain refused to answer when asked about reports that the whole episode was a security drill. He said a statement would be made later on Thursday.
An Indian Airlines pilot, a friend of Capt Behl, said that such drills had taken place before. He said one on a smaller scale, that went unreported, occurred last year.
When the plane arrived in New Delhi, the pilot taxied it to a secluded spot. It was surrounded by commandos, and blocked from taking off by fuel tankers.
Passengers used mobile phones to call their relatives, waiting at the Indira Gandhi International Airport in New Delhi, saying they were fine and knew nothing about a hijack.