The top U.S. military officer says the missile strike that reportedly killed a key al-Qaida commander in northern Pakistan was a "very important" one in the war on terrorism.

Admiral Mike Mullen, chairman of the Joint Chiefs of Staff, said Friday that the attack on Abu Laith al-Libi was "very lethal." He would not comment on the specifics of the operation.

Pakistani intelligence officials based in Miran Shah said Friday they believe Libi was killed earlier this week by a missile fired by a U.S. drone at an al-Qaida hide-out in the North Waziristan tribal region. The missile strike killed at least 12 militants.

Libi, a Libyan national, was one of the top al-Qaida operatives in Afghanistan, with links to the Taliban. He was on a U.S. list of 12 "most wanted" terrorists.

U.S. officials say Libi was involved in a number of attacks against U.S. and coalition forces, including last year's suicide bombing at a U.S. military base near Kabul. That attack at the Bagram base killed 23 people during a visit by U.S. Vice President Dick Cheney.

A radical Islamist website on Thursday announced the death of Libi, calling him a "martyr." The message did not give a cause of death.

Some information for this report provided by AP and AFP.