Washington, Jun 6 (IANS): In another "serious blow" to Al Qaeda, a US drone strike in Pakistan killed its No. 2 leader Abu Yahya al-Libi, who helped steer the terrorist group after Osama bin Laden's death, the White House has confirmed.

Al-Libi's death was "another serious blow to core Al Qaeda," White House spokesman Jay Carney told reporters Tuesday.

"His death is part of the degradation taking place in core Al Qaeda in the last several years."

However, Carney was unable to provide further details. Earlier Tuesday, US officials said that al-Libi was killed by a CIA drone strike in Pakistan launched Monday. Al-Libi's death marks one of the most significant blows to Al Qaeda since the US military killed Osama bin Laden in a daring nighttime raid on his hideout in Abbottabad, near Islamabad on May 2 last year.

Al-Libi was second-in-command behind Al Qaeda leader Ayman al-Zawahiri, who took the helm after bin Laden's death.

"There is no one who even comes close in terms of replacing the expertise (Al Qaeda) has just lost," CNN cited an unnamed US official as saying.

Al-Libi "played a critical role in the group's planning against the West, providing oversight of the external operations efforts," the official said adding, "Zawahiri will be hard-pressed to find any one person who can readily step into Abu Yahya's shoes."

"In addition to his gravitas as a longstanding member of AQ's leadership, Abu Yahya's religious credentials gave him the authority to issue fatwas, operational approvals and guidance to the core group in Pakistan and regional
affiliates."

An Islamic scholar and high-ranking member of the group, al-Libi frequently appeared in Internet videos, CNN said. He gave many videotaped speeches praising Al Qaeda leaders, urging resistance and trying to recruit new members.