School bombers killed in Pakistan's Swat valley

MINGORA, Pakistan (Reuters) - Three Islamist militants were killed by their own explosives while planting a bomb at a girls' school in Pakistan's northwestern Swat valley on Wednesday, police said.

Nearly 150 people, including about 100 pro-Taliban militants, have been killed in clashes with security forces that broke out there last week.

A spokesman for Pakistani Taliban leader Baitullah Mehsud warned that the group would re-start a suicide bomb campaign unless the military stopped attacking its allies in Swat.

"We don't want fighting but if government starts an operation or continues its action in Swat, we'll retaliate and will carry out suicide bombings wherever we could," Taliban spokesman Maulvi Omar.

Two men were killed in clashes on Wednesday in the region.

Swat erupted in violence late last year when a radical cleric called Fazlullah launched a campaign to force people follow strict Islamic laws in the alpine valley that was once a favourite tourist destination, a little over four hours drive from the capital of Islamabad.

The election of a civilian government this year saw a lull in the violence as the new leaders sought to make peace deals in various trouble spots around North West Frontier Province and the semi-autonomous tribal lands.

But the violence began to flare again in recent weeks.

Militants have destroyed bridges, government offices and several girls' schools, but this time the militants were killed by their own bomb.