Interrogations of the Afghan Taliban's No. 2 leader have started producing useful intelligence on the group and its operations against U.S. forces across the Pakistani border, U.S. officials said on Tuesday.

Mullah Abdul Ghani Baradar was captured in the Pakistani port city of Karachi in late January in a joint operation by the CIA and Pakistan's Inter-Services Intelligence (ISI) spy agency.

Direct U.S. access to Baradar, who is in Pakistani custody, was minimal at first. But U.S. officials said the ISI has eased restrictions and American investigators have been participating regularly and directly in interrogation sessions for at least the past month.

Some of the information given by Baradar, the Afghan Taliban's longtime military commander, has been verified and has been useful to U.S. commanders and intelligence officers and analysts in both Afghanistan and Washington, three U.S. officials involved in the matter said.

They spoke on condition of anonymity because of the sensitivity of the issue and would not discuss the nature of the information or describe what interrogation methods were used. They said Pakistan was taking the lead.

"These things take time," one U.S. military official said of interrogating Baradar. "It takes time to get the information and it takes time to check out that information."

"He started sharing information that is useful," another official said.

Baradar's arrest was hailed by the commander of U.S. and NATO forces in Afghanistan, Gen. Stanley McChrystal, as a potential game-changing development after eight years of war, although some U.S. officials initially played down the value of the information he gave Pakistani interrogators.

SIGNS OF TALIBAN DISCORD

Since his arrest, U.S. military officials have pointed to signs of discord within Taliban ranks that could weaken the insurgency. Baradar, who was close to the group's reclusive chief, Mullah Omar, was the main day-to-day commander responsible for leading an increasingly bloody campaign against U.S. and NATO troops, plotting suicide bombings and other major attacks.

But many questions about the capture and Pakistan's motivations remain a mystery months later, such as what intelligence led agents to Baradar's location and what prompted the ISI to act against long-time Taliban allies.

A senior U.S. military official in Kabul described the arrest as part of a power play by Pakistan to ensure it has a major role in any Afghan reconciliation process.

"I think it's a matter of controlling the dialogue," the official said recently, on condition of anonymity. "It's to ensure that they have a ... principal position in a negotiated settlement here, in resolving this conflict.

"I know for a fact that that is the position that the Pakistanis want. They want to ensure that they are not without a big voice in the outcome."

There have been conflicting reports that Baradar might have been talking to Afghan President Hamid Karzai and that may have led to his arrest.

U.S. and NATO advisers in Afghanistan have urged Karzai not to rush into deals with insurgents as part of a national reconciliation process that they envision may take at least three years.