The explosion occurred on Saturday near a civilian car travelling on a desert road connecting the city of Baiji in Salahuddin province with the city of Haditha in Anbar province, Xinhua news agency reported.
The blast destroyed the car, killing two of its occupants and injuring a third, according to Mohammed al-Bazi from the Salahuddin police command media office.
Despite improvements in security since IS's defeat in 2017, remnants of the group continue to conduct guerrilla attacks in Iraq, infiltrating urban centres, deserts, and rugged areas, and targeting both security forces and civilians.