A man named as a key member of a plot to blow up trans-Atlantic airliners has escaped from police custody in Pakistan.

Authorities in Islamabad say Rashid Rauf escaped Saturday in the capital city, where he had appeared in court earlier for an extradition hearing. Police are questioning several officers who were on guard duty at the time.

Rauf, a British national of Pakistani descent, was arrested in Pakistan in August 2006. Authorities in the West say he had a key role in a terrorist plot to blow up passenger airliners traveling between Britain and the United States, using liquid explosives.

More than 20 other people suspected of involvement in the bomb plot were detained in Britain shortly after Rauf's arrest. Disclosure of the alleged terrorists' plan prompted authorities to tighten security procedures at airports worldwide - in particular, restricting the quantity of liquids that air passengers can take with them.

Rauf had been charged in Pakistan with having chemicals that could be used to make explosives, as well as false identification papers. He also faces murder charges in Britain involoving the death of his uncle five years ago.

Pakistani authorities dropped their charges against Rauf last month and began proceedings to extradite him to Britain.