Islamabad  - At least three paramilitary troops were killed and half a dozen more injured in a suicide attack in Pakistan's restive north-western Swat valley on Tuesday, officials said.

"A car suicide bomber struck at a camp of paramilitary Frontier Corps in Totano Bandi area of Kabal sub-district late in the night," army spokesman Major Murad Khan told Deutsche Presse-Agentur dpa.

Following the attack, the militants fired several rockets at the militants, triggering a firefight which continued for several hours.

Swat, previously a popular tourist destination in North West Frontier Province, has seen intensive fighting since last October when Islamabad dispatched thousands of military troops to quell the rebellion of the followers of a radical cleric, Maulana Fazlullah.

He had launched an armed campaign to enforce Taliban rule in the area. His spokesman Muslim Khan claimed the group's responsibility for the attack saying it was carried out to avenge ongoing military operations in Swat and tribal region along Afghan border. (dpa)