Pakistani Taliban attacked an office of the security force's intelligence agency in the country's northwest on Monday, taking several hostages before police stormed the building and ended the siege, police said.
The attack took place in the city of Bannu just outside of the militant stronghold of North Waziristan in the rugged tribal region near the border with Afghanistan.
Police official Zeenatullah Khan said police cordoned off the building and exchanged fire with the attackers. The roughly five-hour siege ended after police stormed the building and rescued the hostages.
Initial reports indicated that one police officer was killed in the attack, but police official Zahid Khan from Bannu said no police died. Three were wounded, he said.
He said security forces caught two of the attackers while another was killed by police gunshots and a fourth exploded his suicide vest.
The Pakistani Taliban claimed responsibility for the attack.
"They are our fighters. They are fighting. There are two suicide bombers," said Ahsanullah Ahsan, a spokesman for the Taliban. He spoke to The Associated Press by telephone from an undisclosed location.
Because of Bannu's proximity to North Waziristan, militant fighters often launch attacks on Pakistani government facilities in the city and then retreat back into the tribal region where it is almost impossible for the security forces to track them.
In April, Pakistani Taliban fighters broke into a prison in the city and freed close to 400 prisoners, including 20 who were considered dangerous insurgents.
Meanwhile, Pakistani health officials have launched a nationwide anti-polio vaccination drive intended to protect the country's children from the potentially paralyzing disease. But vaccinations will not be given in the tribal areas of North and South Waziristan after top Taliban commanders there banned the vaccinations until the U.S. stops drone attacks in the region.
Pakistan is one of only three countries where the disease is endemic. The virus usually infects children living in unsanitary conditions, attacks the nerves and can kill or paralyze.
The government, teaming up with U.N. agencies, is on a nationwide campaign to give oral polio drops to 34 million children under the age of five. This is the third of four nation-wide anti-polio vaccination campaigns scheduled for this year in Pakistan, said Michael Coleman, a communications specialist with UNICEF's polio campaign.
But vaccination programs, especially those with international links, have come under suspicion in Pakistan ever since it became known that a Pakistani doctor ran a fake vaccination program to help the CIA track down Osama bin Laden. While it has always been difficult to reach areas such as North and South Waziristan due to security concerns, the Taliban threats in June were the first time that militants had actively campaigned against the vaccination programs.
The top health official for the Federally Administered Tribal Area, Dr. Fawad Khan, said that due to the security situation and threats to health workers, the polio campaign in South and North Waziristan has been postponed until the security situation in those areas improves.
A total of 145,000 kids in North Waziristan and 81,000 in South Waziristan were supposed to be immunized during this campaign, he said.
"We will use all possible means once security situation improved to immunize children in Waziristan," he said. "We have to protect our children."
Coleman said there have been 23 reported cases of polio so far this year, compared to roughly 58 for the same time last year. However, the monsoon season is approaching, and the higher temperatures, rains and displacement due to flooding can sometimes increase the disease's transmission.