Al-Masri is believed to have died of non-battle causes, possibly complications from hepatitis, Fox News reported. The information on his death contradicts reports al-Masri was killed in a January CIA strike.

Al-Masri is linked to two major terrorist attack plots. The first is the 2005 London subway bombing, in which al-Masri is credited with recruiting, training and directing the bombers. The second is the liquid explosives bomb plot to blow up transatlantic flights bound for the United States and Canada in 2006.

Al-Masri was among the top al-Qaida leaders and was responsible for external operations, plotting attacks outside the tribal areas of Pakistan, officials said.

Al-Masri probably died several months ago, U.S. officials said, not explaining why news of his death wasn't released earlier.