Pakistani officials have officially confirmed the capture of Mullah Abdul Ghani Brader, the Afghan Taliban's senior military commander and trusted friend to Mullah Omar, the Taliban leader.
Major General Athar Abbas, the chief spokesman of Pakistan's army, announced Mullah Brader's capture on Wednesday, a day after US media reported that he had been seized in the southern Pakistani city of Karachi several days ago.
"At the conclusion of detailed identification procedures, it has been confirmed that one of the persons arrested happens to be Mullah Brader," Abbas said in a written message to reporters.
"The place of arrest and operational details cannot be released due to security reasons."
US and Pakistani media reports, citing unidentified officials, said Mullah Brader was captured during a joint US-Pakistani military operation and was being interrogated by US and Pakistani intelligence agents.
Speaking to Al Jazeera, Hamid Gul, the former head of Pakistan's Inter-Services Intelligence (ISI), said that the fact the arrest had reportedly been made during a joint operation by US and Pakistani agents was "unusual".
"This is rather unusual, one of the top leaders of the Taliban leaders being caught here and that it was reported that this was a joint operation between the US and Pakistan intelligence this was unprecedented," he said.
||Born in Dehrawood district of Uruzgan province, in 1968
||Number two to Taliban founder Mullah Omar
||In charge of Taliban's military operations and financial affairs
||Former defence minister for the Taliban
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But Pakistan's government denied it was working alongside US intelligence services. Rehman Malik, the Pakistani interior minister, called those reports "propaganda".
"We are a sovereign state, and hence we'll not allow anyone else to come and do any operation," he said on Pakistani television.
The US and Afghanistan have repeatedly pressed Pakistan to do more to combat Afghan Taliban and al-Qaeda fighters operating on its territory.
Richard Holbrooke, the US envoy to Afghanistan and Pakistan, welcomed Mullah Brader's arrest, calling it a "significant development".
"There is very little I am going to say here on this subject but it is a significant development," the AFP news agency cited Holbrooke as saying on Wednesday, in the first apparent official US confirmation of the arrest.
"I am not going to join any speculation. I am not in a position to share, this is an intelligence matter but we commend the Pakistanis for their role in this and it is part of the deepening co-operation between us."
The White House, however, has not confirmed Mullah Brader's capture, but it did say that there had been increased co-operation by Pakistani authorities in tackling the Taliban and al-Qaeda.
"I think we have in the course of many months seen an increase in that co-operation," Robert Gibbs, the White House spokesman, told reporters.
"We've seen an increase in Pakistani pushback on extremists in their own country, which I think is beneficial not simply for us."
US media reports described Mullah Brader's arrest as the most significant Taliban figure captured since the start of the Afghanistan war.
He is believed to have been in day-to-day command of the group's leadership council, the so-called Quetta Shura, ever since the group's founder and leader, Mullah Mohammed Omar, disappeared from view in the aftermath of September 11 attacks in 2001.
Al Jazeera's Zeina Khodr, reporting from the Afghan capital, Kabul, said Mullah Brader's capture marked a significant step.
"Mullah Brader would be a very good source, concerning information about the Taliban leadership, simply because as far as we know, he has a very good relationship with Mullah Omar, and their relationship goes back to the days when the Taliban were really in power," she said.
"Mullah Brader was a man in charge of military operations who was given the opportunity to make decisions. The ultimate decisions were made by Mullah Omar, but Mullah Brader really played an important role."
The arrest came as US-led forces across the border in Afghanistan undertake one of Nato's biggest offensives against the Taliban.
The assault, one of the biggest in the eight-year war, is the first test of US President Barack Obama's plan to send 30,000 more troops to Afghanistan, where the Taliban has made a steady comeback since a US-led invasion ousted it from power in 2001.