Pakistani forces killed 40 militants on Thursday as artillery and jet fighters backed ground troops fighting in the Bajaur tribal region, and an air strike hit militants in Swat valley, officials said. Pakistani troops launched an offensive in Bajaur last August, and the military says more than 1,500 militants have been killed while 73 soldiers have also died, though no independent verification of casualties is available. NATO forces launched ‘Operation Lionheart' recently to put pressure along the Afghan side of the border across from Bajaur and squeeze the Taleban and Al-Qaeda militants into areas where they can be attacked more easily. The latest clashes erupted in parts of Mamond and Nawagai districts of Bajaur overnight. “Twenty-four militants, including 11 foreign fighters, probably Uzbeks, and a local commander have been killed in exchanges of fire with security forces in the last 24 hours,” a spokesman for the paramilitary Frontier Corps said. A blast in Mamond on Thursday evening killed at least four people, and the leader of a pro-government tribal militia was among the wounded, according to witnesses. Pakistani troops are also battling militants in the northwestern valley of Swat, and there is widespread expectation the next offensive will target the Mohmand tribal region. Sixteen militants were killed in an airstrike on a school building used by militants in Swat's Matta town on Thursday, a military official said. But there were civilian casualties elsewhere. Seven women and a man were killed when artillery fire hit two houses in Khawazakhela district of Swat, police said. Pakistan has been under pressure from the United States to do more to go after Al-Qaeda and Taleban militants in ethnic Pashtun lands. At the same time, US forces have stepped up missile strikes by pilotless drone aircrafts against militant targets on Pakistani territory, angering Islamabad and straining relations between the allies. Suicide attack A suicide bomber killed at least four people when he blew himself up at a mosque in a restive Pakistani region bordering Afghanistan, officials said. According to a local police official Fazal-i-Rabbi, the blast took place in the mosque run by an anti-militant tribal elder, Haji Rehmatullah. Worshippers were leaving from evening prayers at the mosque 22 kilometers northwest of Khar, the main town of Bajaur tribal region, when the bomber blew himself up, killing four people and wounding three others, said Rabbi. Rehmatullah was killed in the attack and was the the main target of the bomber, he added. Rabbi said casualties could have been much higher, but there were only about 10 people in the mosque when the attack occurred.