Peshawar - At least five security personnel and seven rebels were killed when Taliban rebels ambushed a troop convoy in Pakistan's restive Swat Valley, police said Wednesday.

The caravan of several vehicles of paramilitary Frontier Corps (FC) and police carrying supplies for the troops came under attack in Sarsinai area of sub-district Kabal Tuesday afternoon.

"Four FC soldiers and a policeman were martyred (killed) in the attack, while security forces killed seven militants in the clashes that lasted for several hours," said Swat police chief Dilawar Khan Bangash.

He added that between 15 and 18 troops were still missing.

A local security official who spoke on condition of anonymity said 15 paramilitary troops and two policemen died in the ambush.

"It was a very well-coordinated attack. Taliban first hit the convoy with a roadside bomb and destroyed three vehicles including an APC (armoured personnel carrier). Following this they opened fire with assault rifles and rocket-propelled grenades," he said.

A witness named Shafiullah told Deutsche Presse-Agentur dpa by telephone that he saw the bodies of 15 troops lying at the scene.

According to some reports, Taliban fighters still controlled Sarsinai and the authorities were trying to retrieve the bodies through local mediators.

Taliban spokesman Muslim Khan claimed his comrades had captured two soldiers.

Some 40,000 government troops are fighting the followers of radical cleric Maulana Fazlullah since 2007, when he launched an armed campaign to enforce Taliban rule in the region.

Hundreds of people have died in the fighting but Taliban militants remain defiant and continue targeting police as well as political leaders, in addition to blowing up dozens of girls' schools and music shops.

A brief lull in the violence came earlier this year when the new civilian government started peace talks with the Swat militants and reached an agreement in April. But the accord was suspended in June and the army offensive resumed the following month. (dpa)