At least 18 Taliban militants have been killed in Kandahar province of Afghanistan over the past four days, a security official said on Wednesday."Security forces launched operations against Taliban rebels in Khakriz district on Sunday and since then 18 rebels including Taliban key commander Mullah Khakrizwal were killed," Niaz Mohammad Majahid told Xinhua.Khakrizwal, according to Majahid, had served as military operational commander of Taliban in Khakriz and Arghandab districts and his death could prove to be a big blow to the Taliban fighters in Kandahar province.Taliban militants who have been fighting the government forces in parts of Kandahar and neighbouring Zabul, Helmand and Uruzgan provinces over the past several months, were yet to comment on the situation in Khakriz district.