Pakistani security forces wounded and captured a prominent Taliban commander on Monday in a raid near the border with Afghanistan, intelligence officials said.
Mullah Mansour Dadullah took over as commander of Taliban forces in the southern Afghan province of Helmand after his brother, Mullah Dadullah, was killed by British forces in May.
"We have reports that Mansour Dadullah has been arrested by security officials during an operation," said an intelligence officer, who requested anonymity.
Four of the Taliban commander's comrades were also arrested when security forces, acting on a tip-off, swooped on a house in Gawal Ismailzai village, in the Zhob district of the southwestern province of Baluchistan, the official said.
Interior Ministry spokesmen were not immediately available for comment.
Mansour Dadullah had been involved in negotiations aimed at bringing him and hundreds of his fighters into the Afghan government reconciliation process, Kabul-based diplomats said.
But the prospective deal was scuppered when Afghan President Hamid Karzai expelled two European diplomats involved in the negotiations at the end of last year, saying he had not been informed of the talks.
Taliban leader Mullah Mohammad Omar then dismissed Mansour Dadullah from his command for insubordination, a Taliban spokesman said, a move seen as retaliation for negotiating with foreigners. Dadullah had denied he was dismissed, though Taliban spokesmen confirmed it.
The arrest came days after a senior U.S. official said that al Qaeda leader Osama bin Laden and Mullah Omar were operating from Pakistan.
The U.S. official, who spoke on condition of anonymity, said Mullah Omar and other commanders were directing the insurgency in Afghanistan from Quetta, the capital of Baluchistan.
Pakistan has rejected the charges.
Afghan authorities have long said al Qaeda and Taliban leaders receive refuge in Pakistan's lawless tribal regions, souring relations between the two Muslim neighbours.
The two countries agreed last August to work more closely to fight the joint militant threat and ties have improved.
Many al Qaeda and Taliban militants fled to the Pakistani tribal region after U.S.-led forces toppled the Taliban militia's government in late 2001.
Pakistani forces have carried out operations to clear the border area of militants and hundreds of people, including army troops, have been killed in clashes with insurgents.
In January, a suspected US missile attack killed top al Qaeda commander Abul Laith al-Libi in Pakistan's tribal region of North Waziristan.
(Reporting by Saeed Ali Achakzai and Gul Yousufzai and Jonathan Hemming in Kabul; Writing by Augustine Anthony; Editing by Simon Cameron-Moore and Alex Richardson)