KABUL -- Pakistani authorities, aided by U.S. intelligence, have apprehended more Afghan Taliban chiefs following the capture of the movement's No. 2 figure -- arrests that together represent the biggest blow to the insurgents since the U.S.-led invasion in 2001.
The arrests of more than a dozen Taliban leaders, including known associates of Osama bin Laden, came as militants fought to keep a grip on their southern stronghold of Marjah. Hundreds of militants were holding out against a six-day-old assault by 15,000 U.S., NATO and Afghan troops.
Nine Taliban militants linked to al-Qaida were nabbed in three raids late Wednesday and early Thursday near the port city of Karachi, Pakistani intelligence officials said, speaking on condition of anonymity because they weren't supposed to release the information.
Two Taliban shadow governors also were apprehended in separate raids, Afghan and Pakistani officials said without giving specifics.
The arrests follow the capture in Karachi of Mullah Abdul Ghani Baradar, second only to the Taliban's one-eyed leader, Mullah Mohammad Omar. The White House and the Pakistani army have confirmed Baradar's arrest but have released few details, including when and how he was apprehended.
Pakistani intelligence officials said Baradar was traveling by car on the outskirts of Karachi when agents intercepted his vehicle, arresting him along with three bodyguards. One intelligence official said Baradar has provided "useful" information that led to the arrests of other militants.
They said communications intercepted by U.S. authorities played a key role in tracking and arresting the suspects, who were in Karachi buying timers and other bomb-making equipment. They were taken to Islamabad for questioning.
Pentagon spokesman Geoff Morrell said the U.S. was pleased with the recent arrests. He declined to say whether they were the result of better intelligence or an increased willingness by Pakistan to go after suspected militants.
"What I will say to you, yet again, is that we are enormously heartened by the fact that the Pakistani government and their military intelligence services increasingly recognize the threat within their midst and are doing something about it," Morrell said.
Some of those apprehended included key figures in the Afghan insurgency, while others are members of militant groups that operate just across the border in Pakistan.
Among those arrested were Ameer Muawiya, a bin Laden associate who was in charge of foreign al-Qaida militants in Pakistan's border areas, and Akhunzada Popalzai, also known as Mohammad Younis, a one-time Taliban shadow governor in Zabul province and former police chief in Kabul, according to Mullah Mamamood, a tribal leader in Ghazni province.
Others captured in Karachi included Hamza, a former Afghan army commander in Helmand province during Taliban rule, and Abu Riyad al Zarqawi, a liaison with Chechen and Tajik militants in Pakistan's border area, Pakistani officials said.
Taliban shadow governors -- Mullah Abdul Salam of Kunduz province and Mullah Mohammad in Baghlan province -- were arrested separately in Pakistan about 10 to 12 days ago, according to the Kunduz governor, Mohammad Omar.
The two shadow governors were instrumental in expanding Taliban influence in the north, raising fears the insurgency was spreading beyond its base in the south. Salam was arrested in the Pakistani city of Faisalabad. One of the officials said Salam's arrest was the result of information gleaned from Mullah Baradar.
"He was Mullah Omar's key person in the north," said Omar, the Kunduz governor. "He was a tyrant. He was a cruel person. He strongly rejected the peace process."
Taliban spokesmen have denied the arrests, accusing NATO of spreading propaganda to undermine the morale of Taliban fighters holding out in Marjah against the biggest NATO military operation of the eight-year war.
Thousands of U.S., British and Afghan troops are besieging Taliban-controlled areas around the Helmand province town, linchpin of the militant's southern supply and drug-smuggling network.
Once Marjah is won, NATO is expected to shift to neighboring Kandahar province, the birthplace of the Taliban.
Squeezing the Taliban goes hand-in-hand with U.S. Gen. Stanley McChrystal's strategy to convince the insurgents they can't win and offer militants a way to leave the Taliban. The Afghan government is finalizing a plan to coax low- and mid-level fighters to switch sides in exchange for economic incentives and to lure the Taliban's top echelon into reconciliation talks.
Baradar is considered a pragmatic Taliban leader, prompting some experts on the region to speculate that he was captured so he could liaise with the Taliban leadership. Asked about that theory, Richard Holbrooke, the U.S. special envoy to Afghanistan and Pakistan, told reporters this week in Kabul: "I've read the speculation, but I'm not going to join in it except to say that it seems pretty fanciful to me."
U.S. officials have complained for years that Pakistan was protecting key Taliban figures in an apparent bid to maintain influence in case the movement returned to power.
Shaun Gregory, a Pakistan expert at Britain's Bradford University, said he thought Pakistan likely cooperated in the sweep because of "some sort of promise or guarantee from the Americans that it will have a significant role as the reconciliation process goes forward."