The Taliban's top military commander was captured in Pakistan, US and Pakistani officials said today, but the move may not deal a decisive blow to a group putting up fierce resistance to a Nato offensive.
The Afghan Taliban denied that Mullah Abdul Ghani Baradar was captured in a joint raid by Pakistani and US spy agencies.
Washington hopes Mullah Baradar's capture will at least temporarily weaken the Taliban-led insurgency in Afghanistan, where US Marines are leading one of NATO's biggest offensives of the 8-year war, in the southern militant stronghold of Marjah.
"I would call it significant," a US official said on condition of anonymity.
"But even when you get their leaders, they've shown an amazing resilience to bounce back. It's an adaptive organisation."
A second US official confirmed the capture.
A Pakistani security official who declined to be identified said: "Yes, it's true. He has been arrested. He's in our custody."
The New York Times said the capture took place in the southern Pakistani port city of Karachi several days ago.
The capture of Mullah Baradar suggested there is a new level of cooperation between Washington and Islamabad, given that the raid was led by members of the Pakistan's Inter-Services Intelligence agency (ISI) with help from the US CIA.
The United States has long pressured Pakistan to move against Afghan Taliban groups, which it has cultivated for years to use as a future counterweight to old enemy India in Afghanistan.
"It's very clear to me that the Pakistanis understand that this fight is for them and it's a fight for everybody who is going to stand up against terrorism," US Senator John Kerry told CNN after he met Pakistan's army chief, president and prime minister.
A Taliban spokesman said Mullah Baradar was in Afghanistan actively organising Taliban military and political activities.
"He has not been captured. They want to spread this rumour just to divert the attention of people from their defeats in Marjah and confuse the public," Zabihullah Mujahid told Reuters, referring to the Nato offensive.
In a sign of how tough it is to gather intelligence on the Taliban, there have been conflicting reports on who is winning the battle in Marjah, a breeding ground for militancy and poppy cultivation which Western states say finances the insurgency.
Some Marine units have been bogged down by heavy Taliban gunfire, sniper attacks and booby traps.
Much of the success of the offensive depends on limiting civilian casualties to ensure that the local population does not turn against the government and Afghan forces.
The Taliban said on their website today they were in control of Marjah district and that troops had not made any progress beyond the areas where they were transported by helicopters on Saturday at the first stage of the operation.
Ghulam Mahaiuddin Ghori, a senior Afghan National Army general for the southern region, said many Taliban militants had "escaped" and Afghan forces had reached the stage where they were searching houses for arms and ammunition.
Reuters