A key commander of the Taliban militant group was killed during a drone attack in Afghanistan's Kunar province, a police official said on Monday."Acting upon intelligence report, security forces conducted a drone attack on Taliban hideouts in Chapa Dara district on Sunday evening, killing key Taliban commander Mullah Asmatullah," the official said.According to security sources, Mullah Asmatullah was the commander of some 100 fighters and his elimination could prove to be a major setback to the militant group, Xinhua reported.