A former Taliban commander who recently defected from the fundamentalist movement to join the ISIS terror group has been killed in southern Afghanistan, NBC News reported based on local intelligence officials.

Abdul Rauf, apparently a former detainee of the the Guantanamo Bay facility for enemy combatants, had resumed activities with the Taliban when he was released from U.S. custody, said Mohammad Jan Rasoulyar, the deputy governor of Helmand province. He recently split from the group to join ISIS, the organization that calls itself the "Islamic State" and controls large swaths of territory in Iraq and Syria, Rasoulyar added.

"Today at (3.58 a.m. Eastern Time), in a successful operation, Abdul Rauf, also known as 'Khadim,' was killed along with his five companions in Sadat village of Kajaki district of Helmand province," Afghanistan's National Directorate of Security said in a statement. "He was the commander of (ISIS) in southern Afghanistan."

Ashton Carter, President Barack Obama's nominee to lead the Department of Defense, told Congress last week that ISIS may be trying to expand into Afghanistan. The Afghani directorate, meanwhile, would not say exactly how the attack was executed, but local officials told NBC News that Rauf was killed in a NATO strike.

"Rauf and his men were ... killed in a coalition airstrike this morning as they were traveling," Rasoulyar detailed. "The operation took place in close coordination with Afghan security forces." The commander "was travelling in a car along his close men when came under attack," a local government administrator of Kajaki district confirmed.

When in U.S. custody, Rauf had been deemed to be of medium intelligence value because of his possible knowledge of Taliban leadership and command, the Independent noted. The detainee had denied links to senior Taliban officials, but experts dismissed his account as implausible because he served three tours with the fundamentalist group.

Militants said Rauf fought the Soviets in the 1980s and held important positions in the Taliban's government before it was toppled by U.S.-backed forces in 2001, according to NBC News. "He had lost one of his legs during the war against Russians and was thus known as 'gud Mullah' -- or 'Mullah of one leg' -- in Taliban circles," a local commander told the channel.