Washington ? In what could be one of the hardest blows to al-Qaida since the U.S. campaign against the terrorist organization began, the group’s No. 3, Sheikh Sa’id al-Masri, is believed to be dead, killed by a U.S. Predator drone strike, a U.S. official said Monday.

The official, speaking on condition of anonymity, said word was “spreading in extremist circles” of his death in Pakistan’s tribal areas in the past two weeks.

There were multiple postings on Jihadist websites by al-Qaida’s so-called General Command, announcing his death, according to both the IntelCenter and SITE Intelligence Group. SITE said Monday’s announcement also stated that his wife, three of his daughters, his granddaughter, and other men, women and children were killed.