Tension continues to simmer in Pakistan's Swat valley with fresh troop build-up while the extremists loyal to pro-Taliban cleric Maulana Fazlullah have released 48 captured soldiers.

The militants paraded before the media the 48 soldiers on Friday who were taken hostage after a clash with the insurgents in the mountain of Khwazakhela on Thursday.

Television crews were allowed to videotape conversations with the detainees in the troubled valley where fighting among rebels and security forces was on since the past week.

"The captured security officials were released and they were given Rs 500 each as pocket money," said Maulana Fazlullah's spokesman Maulana Sirajuddin.

One of the purported soldiers shown to reporters at Charbagh town, 15 km northeast of the regional capital Mingora, said the rebels had surrounded their hilltop outpost.

"We had exhausted our rations and ammunition. We had no option but to surrender," one of the soldiers was quoted as saying by Geo News, who did not give his name and like the others was not wearing his uniform.

Masked militants brandished assault rifles, rocket launchers and traditional curved Swati swords as they paraded the soldiers.

Due to uncertainty in Swat, the police station of Matta and Khwazakhela have been vacated and the police contingent present there has been deputed in various police stations besides Madyan police station, said Pakistan military sources.

The Swat valley is virtually under the control of insurgents who are sympathetic to Taliban and want imposition of Shariat law and engage in regular skirmishes with security forces to assert their authority over the region.