PESHAWAR (AFP) - Militants blew up a girls school in South Waziristan where a full-scale army offensive is expected against Taliban warlord Baitullah Mehsud, officials said Thursday. The incident came three days after rebels bombed two other schools, one in Peshawar and the other in Bajaur tribal region. A girls high school was blown up early Thursday morning in Shin Warsak town, 13 kilometres west of Wana, the main town in South Waziristan tribal region, local government official Allah Bagh Khan said. He added that there was no loss of life in the explosion but it completely destroyed the school building. Militants have destroyed hundreds of schools, mostly for girls, in northwest and its troubled tribal regions during the past couple of years. At least 200 girls schools in the scenic Swat valley were bombed.