Peshawar, Pakistan - The Taliban blew up on Friday three schools in north-west Pakistan where troops are fighting against militants in the tribal region bordering Afghanistan, officials said.

Buildings in two boys' schools about 1,5 kilometres apart were blown up in the Khyber tribal district which lies between Afghanistan and Peshawar, the capital of North West Frontier Province.

"Militants blew up a government boys' high school and a middle school with explosives around 3.00am (21.00 GMT)," tribal administration official Rehan Gul Khattak told AFP.

There were no casualties because the properties were empty at the time, he said, blaming the Taliban and militants from the Lashkar-e-Islam (Army of Islam) led by local warlord Mangal Bagh for the attacks.

Another government boys high school was bombed in the Peshawar district of Sufaid Dheri, damaging its boundary wall and two rooms, senior police official Mohammad Karim told AFP.

Islamist militants opposed to co-education and subscribers to sharia law have destroyed hundreds of schools, mostly for girls, in north-west Pakistan in recent years.

The Khyber tribal region is the main land bridge to neighbouring Afghanistan and the principle supply route for NATO troops fighting an eight-year Taliban insurgency across the border.

Pakistani troops launched an offensive in Khyber in September in a bid to flush out the Taliban and homegrown Lashkar-e-Islam.

The United States is increasing pressure on Pakistan to crack down more on militants hiding out in its lawless tribal belt, branded the most dangerous place on the planet and the chief sanctuary of al-Qaeda. - Sapa-AFP