The top US commander in Afghanistan has said al-Qaeda will not be defeated unless its leader, Osama Bin¹ Laden², is captured or killed.

美国驻阿富汗最高司令官称，基地组织不会被打败，除非抓获或者捕杀其领导人奥萨玛·本拉登。

Testifying证明，作证 to US Congress, Gen Stanley McChrystal said Bin Laden had become an "iconic figure标致性人物".

He said President Barack Obama's deployment³ of 30,000 extra troops to Afghanistan meant success was possible.

But he said the mission was "undeniably difficult" and the next 18 months would be crucial.

"I don't think that we can finally defeat al Qaeda until he's captured or killed," said Gen McChrystal of Bin Laden.

"I believe he is an iconic figure at this point在这一点上, whose survival emboldens⁴壮胆，鼓励 al-Qaeda as a franchising⁵ organization特约经营组织 across the world," he said.

The general said that killing⁶ or capturing Bin Laden would not spell the end of al-Qaeda but that the movement could not be eradicated⁷被根除的 while Bin Laden remained at large.

The militant⁸ leader is believed to be living in the border region between Pakistan and Afghanistan.

US Secretary of Defense⁹ Robert Gates said last week that officials have had no reliable information on Bin Laden's whereabouts下落 for "years".

'Significant costs'

Gen McChrystal told the Congressional hearing the next 18 months would be crucial in Afghanistan, but that he did not expect to need more troops to get the job done.

He said coalition¹⁰ forces联合部队 faced "a complex and resilient有弹力的，愉快的 insurgency¹¹" and that Afghans lacked confidence in their government.

"Success will require steadfast¹²坚定的，踏实的 commitment and incur招致，蒙受 significant costs," he told the House Armed Services Committee.

The commander said the 30,000 US reinforcements增援部队 would "provide us the ability to reverse insurgent叛乱的 momentum¹⁵ and deny the Taliban the access to the population they require to survive".

He said he did not think he would need to ask for any more troops in a year's time, but would not hesitate to recommend more if circumstances changed.

The US ambassador to Afghanistan, Karl Eikenberry, who reportedly questioned the troop build-up during White House deliberations考虑，研究 last month, also endorsed支持，赞同 the new approach as "the best path to stabilise Afghanistan".

Mr Eikenberry agreed with Gen McChrystal that Bin Laden was key that process.

He said it was "important to the American people - indeed, the people of the world - that one day Osama bin Laden is either captured or killed, brought to justice".

The new battle plan includes an 18-month timeline时间表 before the first US troops would begin to come home.