BAGHDAD, April 8 (Xinhua) -- Iraqi forces on Monday killed four Islamic State (IS) militants in the country's western province of al-Anbar, while a policeman and a child were killed in the central province of Salahudin, security sources said.

The Iraqi army, backed by paramilitary tribal fighters, clashed with IS militants at a desert area west of the town of Haditha, some 200 km northwest of the Iraqi capital Baghdad.

It killed four of the extremist militants, said Qasim al-Mohammadi, commander of al-Jazira Operations Command in Anbar.

In a separate incident, a mortar round landed on a security checkpoint east of the town of Shirqat, some 280 km north of Baghdad, killing a policeman and an eleven-year-old school child, said Mohammed al-Bazi, from Salahudin Provincial Police Command.

The school child was in the checkpoint waiting for a car to take him to his village after he left his school, Bazi said.

In December 2017, Iraq declared full liberation from the IS after the security forces and the paramilitary Hashd Shaabi units, backed by the anti-IS international coalition, recaptured all areas once seized by the extremist group.

However, IS remnants have since melted in urban areas or resorted to deserts and rugged areas as safe havens, carrying out guerilla attacks from time to time against the security forces and civilians.