"The strike also killed one other Harakat al Nujaba member," said Major General Patrick Ryder, a Pentagon spokesperson, describing it as a self-defense strike. "No civilians were harmed. No infrastructure or facilities were struck."

Since the Israel-Hamas war began in October the U.S. military has come under attack at least 100 times in Iraq and Syria, usually with a mix of rockets and one-way attack drones.

The United States has 2,500 troops in Iraq and 900 in neighboring Syria focused on preventing a resurgence of Islamic State militants.