Top Al Qaeda Leader Abu Ubaida al-Masri Confirmed Dead in Pakistan

Abu Ubaida al-Masri, one of Al Qaeda's top operatives and the mastermind behind a plot to use liquid explosives to blow British passenger jets out of the sky, is dead, a U.S. official confirmed to FOX News Wednesday.

The unidentified official said it is believed that al-Masri died of natural causes, possibly hepatitis, in Pakistan, and are staying away from a report that he was killed in a January CIA predator strike.

At the time of his death, the Egyptian-born al-Masri was responsible for the terror organization’s external operations, focusing on plotting attacks outside the tribal areas of Pakistan.

Al-Masri is tied to two major terrorist plots.

The first being the July 7, 2005, London subway bombing, in which al-Masri recruited, trained and directed four homicide bombers in a coordinated attack on London's transportation system. In the attack, known as the 7/7 Bombings, three bombs exploded during morning rush-hour within 50 seconds of each other on three London Underground trains. A fourth bomb exploded on a bus nearly an hour later. The attack left 52 commuters dead, and more than 700 injured. It was the largest and deadliest terror attack on London in its history.

The second plot, in August, 2006, involved the use of liquid explosives smuggled aboard several airliners traveling from London's Heathrow and Gatwick airports to major cities in the U.S. and Canada with the intention of detonating the bombs in midair, destroying at least 10 aircraft.

British intelligence foiled that plot, arresting 24 suspects in and around London. Eight of the original suspects currently are on trial in London, charged with conspiring to murder and destroy aircraft.

U.S. officials say al-Masri probably has been dead for several months, with no explanation as to why news of his death was not released sooner.

Few have heard of al-Masri outside a select circle of anti-terrorism officials and Islamic militants, the Los Angeles Times reported last week.

"Abu Ubaida al Masri" is an alias, and officials have yet to learn the mysterious operative's real name, the Times reported.

"He is considered capable and dangerous," an unidentified British official told the newspaper. "He is not at the very top of Al Qaeda, but has been part of the core circle for a long time. He is someone who has emerged and grabbed our attention as others were caught or eliminated in the last couple of years. Perhaps he rose faster than he would have otherwise."

Al-Masri was in his mid-40s according to a German investigative file obtained by the Times. His alias means "The Egyptian Father of Ubaida." Little is known about his youth other than that he belonged to a generation of Egyptians who have dominated Al Qaeda since the terror group fought the Soviets in Afghanistan in the 1970s and '80s, the Times reported.

Al-Masri fought in Bosnia-Herzegovina in the early 1990s, went on to Chechnya and lost two fingers in combat — leading to the nickname "Three-Fingered Egyptian" — the investigative file cites. He surfaced in Germany in 1995 requesting asylum, which was rejected in 1999. He was jailed pending deportation, but was then released for unknown reasons, the newspaper reported.

An associate of al-Masri in Germany included a Moroccan computer science student who married the daughter of Ayman Zawahiri, Usama bin Laden's deputy, the newspaper reported. By 2000 al-Masri was back in Afghanistan serving as an explosives instructor at a training camp near Kabul.

During the U.S.-led military operation in Afghanistan in late 2001, Masri fought in a paramilitary unit that took heavy casualties covering bin Laden's escape into Pakistan, Rohan Gunaratna, author of "Inside Al Qaeda," told the newspaper.

When the self-proclaimed Sept. 11 mastermind Khalid Shaikh Mohammed was captured in 2003, al-Masri joined a group of chiefs responsible for external operations, the Times reported.

"He's considered a player," a U.S. anti-terrorism official told the newspaper.

Click here for more from the Los Angeles Times.