ISLAMABAD, Pakistan — A leading al Qaida military commander thought to have played a role in planning the 2008 terrorist attacks in Mumbai has been killed by an American missile strike in Pakistan’s tribal area, his extremist group confirmed Saturday, while vowing revenge on the United States.

Ilyas Kashmiri was one of the most wanted militants in the world, carrying a $5 million American bounty on his head. He was among the four or five names on a list handed over to Islamabad last month by Secretary of State Hillary Clinton as the extremists that Washington wants hunted down in joint operations in Pakistan. The other names included al Qaida deputy leader Ayman al Zawahiri and Taliban founder Mullah Omar.

Last month’s spectacular attack on a Pakistan naval base was reportedly masterminded by Kashmiri. Some believed that he was al Qaida’s military commander or even a possible successor to Osama bin Laden, the al Qaida chief killed by a U.S. special forces team in Pakistan last month.

Islamabad routinely protests against U.S. missile strikes in its territory, by unmanned drone aircraft, as a breach of sovereignty, while the Pakistani media also energetically denounces them. But Kashmiri also was one of Pakistan’s most wanted terrorists, possibly the most dangerous man for the country, and such condemnation was conspicuously absent this time. The drone strike program has slowed down this year, apparently as a result of Pakistan’s protests.

Kashmiri headed the feared “313 Brigade”, a break-away faction of jihadist group Harakat-ul-Jihad al-Islami, that was closely associated with al Qaida. His group, in a fax sent to Pakistani news outlets Saturday, confirmed Kashmiri was "martyred" in a drone strike Friday night in the South Waziristan part of the tribal region.

“God willing, America, which is the 'pharaoh' of this, will soon see a revenge attack, and our real target is America,” the hand-written statement said.

It was not possible to verify the authenticity of the fax and some extremists reported killed in drone strikes have later turned out to be alive — including Kashmiri himself in 2009.

Kashmiri had been thought to be hiding in the tribal area, which runs along the Afghan border, since 2007, from where he trained and directed extremists to carry out attacks in Pakistan and beyond. He was reportedly a former Pakistani special forces soldier and he specialized in commando-style gun assaults.

According to a book, Inside al Qaida and the Taliban just published by Syed Saleem Shahzad, a Pakistani journalist murdered last month, Kashmiri was behind the devastating 2008 terrorist assault on the Indian city of Mumbai, which killed 166 people.

Kashmiri is indicted in an on-going terrorist trial in Chicago related to the planning of the Mumbai attack, though that indictment names him specifically only in a plot to attack a newspaper in Denmark.