A member of paramilitary Hashd Shaabi units and a woman were killed on Friday in two attacks by Islamic State (IS) militants in Iraq's central province of Salahudin, a provincial security source said.

Early in the morning, IS militants attacked a security checkpoint manned by Hashd Shaabi fighters near al-Zouyah in north of Salahudin's provincial capital Tikrit, located some 170 km north of Baghdad, sparking a heavy clash, Khalil al-Bazi from the provincial police command told Xinhua.

The clash left a Hashd Shaabi member killed and another wounded, while the extremist militants fled the scene after the arrival of reinforcement troops, al-Bazi said.

In a separate incident, a roadside bomb believed to be planted by IS militants struck a civilian car on a main road near the town of Baiji, some 30 km north of Tikrit, killing a woman and wounding her husband and her three children, al-Bazi added.

The security situation in Iraq has dramatically improved after Iraqi security forces fully defeated the IS late in 2017.

But IS remnants have since melted into urban areas or used deserts and rugged areas as safe havens, carrying out frequent guerilla attacks against security forces and civilians.