A key Taliban commander in southern Afghanistan has been dismissed for disobeying the militant group's rules, a Taliban spokesman said. Mansoor Dadullah was "disobeying orders" and conducting activities "against the Taliban's rules and regulations," Taliban spokesman Zabiullah Mujahid said Saturday. He did not provide any details. "For this reason Mullah Mansoor Dadullah is no longer in the Taliban and no longer a Taliban commander," Mujahid said in a statement he attributed to Taliban leader Mullah Omar. Dadullah rose in the militia's ranks as a key commander in southern Afghanistan after his brother, Mullah Dadullah, was killed during a military operation last May in Helmand province. Mullah Dadullah was the highest-ranking Taliban commander killed since the US-led invasion of Afghanistan in 2001.