Three soldiers were killed and one was wounded in an attack on Sunday evening on a military post in western Iraq, the government said.
No group has claimed responsibility for the attack in the town of Haditha, but the Iraqi government claimed ISIS extremists were to blame.
It did not elaborate.
The attackers, armed with sniper rifles and semi-automatic weapons, arrived in two vehicles, a military official told The National. They fled the area after the attack, he said.
Haditha is located about 190km west of Baghdad.
The attack comes amid the Iraqi government's attempts to bring to an end the presence of the US-led International Coalition, which was formed to fight ISIS. They argue that Iraqi security forces are capable of facing the militants themselves.
The request followed an escalation in clashes between the US military and Iran-backed Shiite militias since the outbreak of the Gaza war. The US military has retaliated with air strikes that have so far killed 17 militants, including a senior leader.
“We are in the process of reorganising this relationship,” Prime Minister Mohammed Shia Al Sudani said late last month at a press conference in Baghdad with Prime Minister Pedro Sanchez of Spain, which also has troops in Iraq.
“With the presence of capable Iraqi forces, the Iraqi government is heading towards ending the presence of the international coalition forces," Mr Al Sudani said.
Iraq seeks to 'end presence' of US-led forces in country
ISIS surged across northern Iraq and Syria in 2014, seizing the cities of Raqqa and Deir Ezzor in Syria and Mosul in northern Iraq.
Iraq declared victory over ISIS in December 2017, but the group still operates in isolated pockets of the north and west of the country, carrying out ambushes, assassinations and bombings.
Estimates of the group's strength vary. The CIA estimated that ISIS had between 20,000 and 30,000 fighters at its peak in 2014, while Russia estimated a total force of more than 70,000.
Iraqi officials estimate the group's members now number in the hundreds.
American troops make up the largest contingent of foreign forces based in Iraq as part of the international coalition formed to defeat ISIS. They stayed on after ISIS was defeated to help Iraqi forces mop up sleeper cells and prevent the group's resurgence.
