The US will hunt down and kill new al-Qaeda leader Ayman al-Zawahiri as it did Osama Bin¹ Laden², Washington's top military officer has vowed³.

华盛顿高级军官发誓，美国将像对待本拉登一样追捕并杀死基地组织新领导阿伊曼·阿尔-扎瓦希里。

Zawahiri had been widely anticipated to replace Bin Laden at the helm
Adm Mike Mullen said al-Qaeda still posed a threat to the US.

"As we did both seek to capture and kill - and succeed in killing⁴ - Bin Laden, we certainly will do the same thing with Zawahiri," he said.

Zawahiri's appointment was posted on a militant⁵ website and attributed to al-Qaeda's General Command.

"There is not a surprise from my perspective（观点，远景） that he has moved into that position," Adm Mullen, chairman of the Joint⁶ Chiefs of Staff, told journalists.

Zawahiri has for a long time been the militant group's second-in-command. Osama Bin Laden was killed by US special forces in Pakistan in May.

'Lacking charisma⁷'

The al-Qaeda statement vowed that that under Zawahiri, it would pursue jihad（讨伐异教徒） or holy war against the US and Israel "until all invading armies leave the land of Islam".

"Sheikh Dr Ayman al-Zawahiri, may God guide him, assumed responsibility as the group's amir [leader]", it said.

An unnamed US official said earlier that Zawahiri had "nowhere near" Bin Laden's credentials⁸（证书，信任状） .

"His ascension（上升） to the top leadership spot will likely generate criticism if not alienation⁹ and dissention（异议） with al-Qaeda," the Obama administration official said, speaking on condition of anonymity¹⁰.

He added that Zawahiri, 59, would find it difficult to lead while focusing on his own survival.

"The bottom line is that Zawahri has nowhere near the credentials that [Osama Bin Laden] had," said the official.

Analysts¹¹ say Egyptian-born Zawahiri is intelligent but lacks the charisma（领袖魅力） of his predecessor¹².

He is claimed by some experts to have been the "operational brains" behind the 9/11 attacks on the US.

For years Bin Laden's deputy, with a $25m (£15m) bounty¹³（慷慨，奖金） on his head, he had been widely anticipated to replace Bin Laden at the helm.

Zawahiri, whose 60th birthday is believed to be this Sunday, warned just over a week ago that Bin Laden would continue to "terrify" the US from beyond the grave.