Ahmed Wali Karzai, a younger brother of Hamid Karzai, Afghanistans president, and one of the countrys most powerful men, has been shot dead by one of his bodyguards, according to a provincial official. Mr Karzai was head of the provincial council in the southern Kandahar province, focus of last years US troop surge, and widely regarded as among the key-power brokers in southern Afghanistan. One of his bodyguards shot him on Tuesday at his house, a heavily-fortified compound in Kandahar city, Zalmay Ayoubi, spokesperson for the governor of Kandahar province said. A guard of Ahmed Wali Karzai named Sardar Mohammad opened fire and killed him. The other guards shot and killed Sardar Mohammad, Mr Ayoubi said. The motive for the shooting was not immediately clear. The Taliban claimed responsibility for the killing, calling it one of our biggest achievements in nearly a decade of war, a foreign news agency reported.