The alleged mastermind of a 2006 transatlantic airplane bombing plot was killed in a US missile attack in northwest Pakistan early on Saturday, officials said.

"The transatlantic bombing plot alleged mastermind Rashid Rauf was killed along with an Egyptian al Qaida operative in the US missile strike in North Waziristan early on Saturday," a senior security official told AFP.

Rashid Rauf escaped in December 2007 from Pakistani police custody. He had been on the way to an extradition hearing after Britain had requested the move.

The British-Pakistani citizen's arrest in 2006 sparked a worldwide security alert and 24 people were detained in Britain in a major swoop.

A day after the arrest a massive security alert was clamped on London's Heathrow Airport, with mass cancellations of flights for several days over fears of a terrorist attack.

He was killed along with at least three other militants in a US drone attack on the house of a local tribesman in the village of Alikhel, part of a district known as a stronghold for al Qaida and Taliban, officials said.