The pilot of Air India's Amritsar- Birmingham flight was on Sunday asked to abort take off and an elderly NRI couple off-loaded and later arrested for allegedly carrying narcotic drugs.

The passengers-a 60-year-old man and a 58-year-old woman-- were off-loaded along with their checked-in baggage and later taken into custody by sleuths of the Directorate of revenue Intelligence (DRI) for allegedly possessing 3.73 kgs of heroin, worth nearly Rs 4 crore in the international market, official sources said.

The flight--IC 187--was ready to take off after the doors of the aircraft--a Boeing 777-200-- had been closed, the sources said, noting that the pilot was asked to return from the runway of the Raja Sansi international airport by the Air Traffic Control (ATC) following a tip off that two passengers could be ferrying narcotics.

After a thorough search, the DRI couple identified as Raminder Singh and Harinder Kaur were arrested, they said, alleging that the contraband was found in their baggage.

The couple were scheduled to fly to Toronto after a stopover at Birmingham, they said, maintaining that the aircraft took off after a delay of over half-an-hour.

The baggage of the passengers had earlier been cleared in the normal course by the airport authorities and the two were allowed to board, they said.