KABUL, Afghanistan — A former Taliban commander who had recently pledged allegiance to the Islamic State militant group was killed in a military operation in Helmand Province on Monday, according to Afghan officials and a tribal elder in the area.

Precise details were unavailable. In announcing the death of the commander, Mullah Abdul Rauf Khadim, the Afghan spy agency said that it had been tracking him for a month, and that he and five of his men had been killed in a “successful military operation” in the Kajaki district of Helmand.

The deputy governor of the region, Mohammad Jan Rasolyaar, said that the actual strike that killed Mullah Khadim had come from an American drone. A spokesman for the American-led military coalition in Afghanistan, Col. Brian Tribus, confirmed that the coalition had conducted a “precision strike” in Helmand that killed “eight individuals threatening the force.” But American officials would not say who was targeted in the strike or whether it was a part of the military operation against Mr. Khadim.

If confirmed, the strike against Mullah Khadim would be the first known military operation undertaken against the Islamic State in Afghanistan, more than 1,000 miles from the group’s home territory in Syria and Iraq.