A doctor at the town's hospital said at least 60 people were wounded and many more people remained trapped under rubble.

Local television reported that the blast destroyed at least 150 homes.

Remote village

Imran Khan, Al Jazeera's correspondent in the Pakistani capital, Islamabad, said the location of the blast was very remote.

"The village is off the radar. It hasn't been seen as a target worthy of an explosion of this size," our correspondent said.

"The size of the crater suggests the number of explosives used was a massive amount. The only time we've seen craters of that size are in major urban centres.

"There is a theory developing that the village itself was not the target and that this could have been some sort of arms or munitions dump where an explosion happened quite by accident."

The blast comes amid a major offensive by Pakistani troops to drive out Taliban fighters from their strongholds in tribal regions near the Afghan border.

While security forces say they have flushed out the anti-government fighters from the North West Frontier Province, an assault is currently under way in South Waziristan to capture Baitullah Mehsud, the Pakistani Taliban leader.

The Taliban has vowed to fight back and launch counter attacks.