When al-Qaida leader Abu Yahya al-Libi arrived in northwest Pakistan several years ago, he commanded so much respect that even some of the world's most dangerous militants held him in awe.

Already a legend in the shadowy world of jihad for breaking out of a high security US prison in neighboring Afghanistan in 2005, he seemed to promise endless funds, training and inspiration for men who dreamed of unleashing carnage in New York or London.

By the time he was killed in a US drone strike last week, he was the latest victim of a series of the unmanned aerial attacks that has crushed al-Qaida's network along Pakistan's border with Afghanistan, Pakistani intelligence officials and commanders of militant groups said.