A former Taliban commander, who had recently sworn allegiance to the Islamic State group, was killed in a U.S. drone strike in the southern province of Helmand on Monday. Five other militants were also killed when the drone targeted a car loaded with explosives in northern Helmand, according to media reports.

Mullah Abdul Rauf, a former member of Taliban in Afghanistan, had been released from the Guantanamo Bay in 2007 after being detained in 2004, according to a U.S. defense department document released by WikiLeaks in 2011. Following his transfer to Afghanistan, Rauf reportedly pledged allegiance to ISIS leader Abu Bakr al-Baghdadi and began actively recruiting for the group in the country.

“People are saying that he has raised black flags and even has tried to bring down white Taliban flags in some areas,” a local Taliban leader told The Associated Press in January.

Rauf’s brother-in-law and four Pakistani militants were also killed in the drone strike, Helmand police chief Nabi Jan Mullahkhel told Reuters.

ISIS, which controls territories in northern Syria and Iraq, has a small but growing presence in Afghanistan, especially in the southern provinces of Zabul and Helmand. In January, ISIS released a video showing the beheading of a Pakistani army soldier, as well as militants from Afghanistan and Pakistan pledging loyalty to the group. In the video, Shahidullah Shahid -- a militant who was identified as a former Pakistani Taliban spokesperson -- claimed that several local militant groups from Pakistan and Afghanistan had pledged loyalty to al-Baghdadi. Later in the same month, the self-proclaimed caliph reportedly accepted this pledge of allegiance.