Blast in NW Pakistan Kills at least 29

A bomb blast at a mosque in Pakistan's northwestern tribal belt killed 29 people including some militants Thursday, underscoring the relentless security threat here even as Pakistani-U.S. cooperation against extremism appears on the upswing.

The attack in Khyber tribal region came as U.S. special envoy Richard Holbrooke met with Pakistan's prime minister in Islamabad, the capital. It also followed revelations that Pakistani authorities have been picking up Afghan Taliban leaders on their soil, a longtime U.S. demand.

The explosion tore through a mosque in the Aka Khel area of Khyber, killing at least 29 people and wounding some 50 others, local official Jawed Khan said. Earlier reports had said the blast occurred in the Orakzai area at a cattle market.

The two areas border one another, and the market is apparently near the mosque.

Officials were still investigating whether the explosion was caused by a suicide bomber or a planted device.

No group claimed responsibility, but Khan said the dead included militants from Lashkar-e-Islam, an insurgent group in Khyber that has clashed with another militant outfit known as Ansarul Islam. Both espouse Taliban-style ideologies.

Earlier this week, officials confirmed that a joint CIA-Pakistani security operation had captured the No. 2 Afghan Taliban commander, Mullah Abdul Ghani Baradar, in the southern Pakistani city of Karachi.

On Thursday, an Afghan official told The Associated Press that around the same time - some two weeks ago - two Taliban leaders from northern Afghanistan also were arrested in Pakistan by Pakistani authorities.

The U.S. and Pakistan have said very little on the record about the arrests, but they could signal a shift in Pakistani policy. Pakistan has long frustrated the Americans by either denying that the Afghan Taliban use its soil or doing little to root them out.

The arrests could mean that Pakistan has decided to turn on the Afghan Taliban, a group that it helped nurture as a strategic ally against longtime rival India, though some suspect the Pakistanis were forced to act because the U.S. had solid intelligence on Baradar that it could not deny.

The arrests came as Western and Afghan troops fight the Taliban for control of Marjah town in southern Afghanistan's Helmand province.

Pakistani Prime Minister Yousuf Raza Gilani told Holbrooke that the U.S. should take into account Pakistan's concerns that the Marjah offensive could lead to Afghan refugees and militants heading to Pakistan's southwest and northwest, according to Gilani's office.

The pair also discussed U.S. humanitarian aid efforts, with Gilani pressing for a quicker release of funds. The U.S. has pledged $7.5 billion in aid to Pakistan over the next five years.

Talking with reporters in Kabul on Wednesday, Holbrooke said the U.S. was restructuring the way it doles out aid to Pakistan and intends to consult more with the Pakistanis and pursue more visible projects.

"It is very, very time consuming work because of the huge, long lead times of contracts, because of the congressional role," he said.