A suicide bomber detonated his explosive vest outside a mosque in a Shiite neighborhood Friday in Pakistan's northwestern Kurram tribal region, killing at least 26 people, government officials said.
Three more people were killed when police shot at protesters from the Shiite community after the bombing in Parachinar, the main town in Kurram, an official said. A curfew was imposed in the town.
The bomber struck outside the mosque in a busy market after Friday prayers, in the latest attack by Sunni militants against minority Shi'ites.
Kurram, the only part of Pakistan's border region that has a significant Shiite population, has been racked by sectarian violence between Sunni and Shi'ite tribes. The Taliban and al Qaeda's virulent anti-Shiite ideology has meant years of bloody fighting.
Fazal Saeed, leader of a breakaway faction of the Pakistani Taliban, claimed responsibility for the latest attack in Kurram, near the Afghan border.
"We have targeted the Shiite community of Parachinar because they were involved in activities against us," he told Reuters by telephone from an undisclosed location.
"We also warn the political administration of Parachinar to stop siding with the Shi'ite community in all our disputes."
Shiite Muslims are a minority sect of Islam, arising from a dispute over the successor to the Prophet Mohammad 1,400 years ago. Many extreme Sunni Muslims consider them apostates.
Saeed was part of the Tehrik-e-Taliban Pakistan (TTP) but broke away last year after disputes with the umbrella militant group's leadership.
He is said to have close ties with the Haqqani militant group, one of the most feared factions of the Afghan Taliban.
The TTP, al Qaeda, and the Afghan Taliban movement fighting Western forces in Afghanistan are entrenched in Pakistan's northwestern tribal areas. All have been involved in anti-Shiite activities for years.
They continue to have strongholds in the region despite a series of military operations in the last few years.
Pakistan's army and air force have been conducting operations against militant groups in Kurram since the beginning of the year. Dozens have been killed in fierce fighting this month.
The blast came as Pakistan's foreign minister said it would be "preposterous" for Afghanistan to expect Islamabad to deliver the Taliban's leader to the negotiating table, as talks between the two countries on the peace process ended with little sign of progress.
The apparent gridlock shows the difficulties inherent in the peace process, which the United States is strongly pushing as a way to end the 10-year-old Afghan war and allow it to withdraw most of its combat troops by 2014 without the country further descending into chaos.
Pakistan is seen as key to the process because Taliban chief Mullah Omar and other senior commanders are believed to be based in the country. Islamabad has close historical ties to the group but has always denied that the Taliban leadership is based within its borders. Analysts say Pakistan can either help the talks or act as a spoiler.
It's unclear whether Afghan President Hamid Karzai asked for access to Omar during his current visit to Islamabad, and he made no public mention of the cleric. But he has called on Pakistan in the past to facilitate contact with the insurgent group's leaders.
Leaders from Afghanistan, Pakistan and Iran held a three-way summit in Islamabad over the past two days that focused on Taliban peace talks, including steps Pakistan could take to help the process, and other regional issues. The summit ended Friday.
However, Pakistani Foreign Minister Hina Rabbani Khar indicated her government was still uncertain on exactly what Afghanistan wanted, saying "they have not conveyed that clarity to us."
Karzai also seemed to indicate the process going forward was uncertain.
"What we need now is to formulate a policy that is actionable and implementable, and actually act upon it," Karzai said at a press conference featuring Pakistani President Asif Ali Zardari and Iranian President Mahmoud Ahmadinejad. Khar's comments came as she spoke to reporters after the press conference.
The foreign minister cautioned against Kabul expecting too much in terms of Pakistan providing access to the Taliban's leaders.
"If you have unrealistic, almost ridiculous expectations, then you don't have common ground to begin with," said Khar.
Khar said that any expectation that Pakistan can deliver the Taliban's chief for talks is "not only unrealistic, but preposterous."
Pakistan and Afghanistan have long had a troubled relationship, one that grew more difficult last year when a suicide bomber assassinated former Afghan President Burhanuddin Rabbani in Kabul. He had been serving as Afghanistan's envoy to Taliban peace talks, and Afghan officials accused Pakistan of playing a role in the killing — allegations it denied.
There have been some signs that momentum for Taliban peace talks has been growing.
The Taliban are setting up an office in the tiny Gulf state of Qatar in the first step toward formal negotiations. Also, the Obama administration is considering releasing five top Taliban leaders from the U.S. detention center in Guantanamo Bay as a starting point for talks.
But the process has also been riddled with rumor and uncertainty.
The Associated Press and Reuters contributed to this report.
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