Thirty Pakistani policemen are reported to have been captured by Taliban fighters in the northwest Swat Valley after they laid siege to a police station.
"Taliban kidnapped 30 policemen and blew up the police office after a day-long fight," Dilawar Khan, a regional police commander, said on Wednesday.
Army troops were sent to the Shamozai area in an effort to rescue the police officers but the operation was suspended after dusk fell, security officials said.
Four paramilitary and police officers were wounded in the clashes around the police station, a Pakistani intelligence official said.
Pakistan has carried out a series of military operations against Taliban-linked fighters in the region in recent months.
Thousands of people living in the Swat valley have fled their homes to escape clashes between government forces and opposition fighters.
Many of the fighters are loyal to Maulana Fazlullah, a religious leader who since mid-2007 has led an armed campaign aimed at promoting Sharia.
Kamal Hyder, Al Jazeera's correspondent in Islamabad, said that scores of public buildings in Swat Valley have been destroyed amid the fighting.
"At least 200 institutions, such as schools, have been destroyed. The government continues to insist that it is Fazlullah's loyalists who have been doing this. The militants themselves say this is not the case," he said.
While visiting the Swat Valley, Hyder found evidence that the conflict is widening from the upper reaches of the valley to other areas.
"The failure of a political settlement has led to a more intense military confrontation here. People here will tell you that the military solution alone will not work," he said
"The provincial government that rules the Northwest Frontier Province [which contains the Swat Valley] has failed totally.
"From what we have seen, the problem has spread from upper Swat and is spreading to lower Swat. What happens next is anybody's guess."
Amir Rana, director of the Pakistan Institute for Peace Studies, speaking in Islamabad, said that the Pakistan government appears not to have a clear long-term strategy.
"Even if the government is successful, what happens next? The whole infrastructure in Swat is destroyed, the administration is nowhere and education systems have totally collapsed," he told Al Jazeera.
"The biggest challenge comes after the elimination of the Taliban ... But the Taliban are intensifying their operations. They are confident."
About 50 militants were killed in military operations across the valley between Monday and Tuesday, security and intelligence officials have said.