ISLAMABAD: The Taliban's top military commander has been arrested in a joint CIA-Pakistani operation in Pakistan in a major victory against the insurgents as U.S. troops push into their heartland in southern Afghanistan, officials said Tuesday. Mullah Abdul Ghani Baradar, the No. 2 behind Afghan Taliban founder Mullah Mohammad Omar and a close associate of Osama bin Laden, was captured in the southern Pakistani port city of Karachi, two Pakistani intelligence officers and a senior U.S. official said. They spoke on condition of anonymity because they were not authorized to release such sensitive information. One Pakistani officer said Baradar was arrested 10 days ago with the assistance of the United States and "was talking" to his interrogators. The New York Times first reported the arrest on its Web site late Monday. Baradar is the most senior Afghan Taliban leader arrested since the beginning of the Afghan war in 2001. Pakistan's spy agency has been accused in the past of protecting top Taliban leaders believed sheltering in the country, frustrating Washington. Moving against Baradar could signal that Islamabad increasingly views the Afghan Taliban, or at least some of its members, as fair game. There was also speculation that the arrest could be related in some way to a new push by the United States and its NATO allies to negotiate with moderate Afghan Taliban leaders as a way to end the eight-year war in Afghanistan. Pakistan has an important role in that process because of its close links with members of the movement, which it supported before the Sept. 11, 2001, attacks. "If Pakistani officials had wanted to arrest him, they could have done it at any time," said Sher Mohammad Akhud Zada, the former governor of Afghanistan's Helmand province and a member of the Afghan parliament. "Why did they arrest him now?" Baradar heads the Taliban's military council and was elevated in the body after the 2006 death of military chief Mullah Akhtar Mohammed Usmani. He is known to coordinate the movement's military operations throughout the south and southwest of Afghanistan. His area of direct responsibility stretches over Kandahar, Helmand, Nimroz, Zabul and Uruzgan provinces. According to Interpol, Baradar was the deputy defense minister in the Taliban regime that ruled Afghanistan until it was ousted in the 2001 U.S.-led invasion. Karachi is Pakistan's largest city and has been increasingly cited as a possible hiding place for top Afghan Taliban commanders in recent months. It has a large population of Pashtuns, the ethnic group that makes up the Taliban, but it is on the Arabian Sea and far from the Afghan border. A Taliban spokesman in Afghanistan told The Associated Press that Baradar was still free, though he did not provide any evidence. "We totally deny this rumor. He has not been arrested," Zabiullah Mujahid told the AP by telephone. He said the report was Western propaganda aimed at undercutting the Taliban fighting against an offensive in the southern Afghan town of Marjah, a Taliban haven. "The Taliban are having success with our jihad. It is to try to demoralize the Taliban who are on jihad in Marjah and all of Afghanistan," he said. The Times said it learned of the operation against Baradar on Thursday but delayed reporting it at the request of White House officials who argued that publicizing it would end a valuable intelligence-gathering effort by making Baradar's associates aware of his capture. The newspaper said it decided to publish the news after White House officials acknowledged Baradar's capture was becoming widely known in the region. Word of Baradar's capture came as U.S. Marine and Afghan units pressed deeper into Marjah, facing sporadic rocket and mortar fire as they moved through suspected insurgent neighborhoods on the third day of a NATO offensive to reclaim the town. U.S.-based global intelligence firm Stratfor said the reported arrest was a "major development," but cautioned it may not have a significant impact on the battlefield in Afghanistan. "It is unlikely that a single individual would be the umbilical cord between the leadership council and the military commanders in the field, particularly a guerrilla force such as the Taliban," it said in an analysis soon after news broke of the arrest. Baradar was not known to be an especially moderate member of the Taliban open to the possibility of peace talks. He gave a written interview to Newsweek last year in which he denied the Taliban's leadership council was based in Pakistan and said the group did not see the point in reconciliation talks with the Afghan government or Washington. "Our basic problem with the Americans is that they have attacked our country," said Baradar. "They are offering talks, hoping that the mujahideen surrender before them. We see no benefit for the country and Islam in such kind of talks."