....The number of Hellfire missile attacks by Predators in Pakistan has more than tripled, with 11 strikes reported by Pakistani officials this year, compared with three in 2007. The attacks are part of a renewed effort to cripple al-Qaeda's central command that began early last year and has picked up speed as President Bush's term in office winds down, according to U.S. and Pakistani officials involved in the operations.

There has been no confirmed trace of bin Laden since he narrowly escaped from the CIA and the U.S. military after the battle near Tora Bora, Afghanistan, in December 2001, according to U.S., Pakistani and European officials. They said they are now concentrating on a short list of other al-Qaeda leaders who have been sighted more recently, in hopes that their footprints could lead to bin Laden. ....

Above all, they said, the search has been handicapped by an inability to develop informants in Pakistan's isolated tribal regions, where bin Laden is believed to be hiding. ....