At least 22 militants were killed and several others injured during clashes with the Pakistan Army in Khyber Pakhtunkhwa province, sources said on Thursday. The sources said the armed forces launched a massive offensive against militants in Upper Dir district near Afghan border. According to sources, the forces shelled militants hide outs in the area. Pakistan Army has been battling a Pakistan Taliban-led insurgency since 2008 in the countrys northwestern restive region.