At least 30 people were killed and 45 others wounded in separate violent attacks across Iraq on Saturday, police and medical sources said.

Four Iraqi soldiers and their taxi driver were killed when they were attacked by gunmen in western Tikrit, some 170 km north of Baghdad, a local police source said.

In Samarra, 120 km north of Baghdad, four members of the Iraqi Federal Police were killed when gunmen attacked their checkpoint, the source said.

In Iraq's western province of Anbar, fierce clashes erupted in the south of the provincial capital city Ramadi, some 110 km west of Baghdad, between Iraqi soldiers and gunmen believed to be linked to the Islamic State of Iraq and Levant (ISIL). Eight militants were killed and eight soldiers wounded, a provincial police source said.

Also in Ramadi, gunmen in army uniforms shot dead a police officer and two policemen in central city, before they fled the scene, the source said.

Also in the province, three civilians were killed and 14 others wounded by the army artillery shelling on several neighborhoods in the besieged city of Fallujah, some 50 km west of Baghdad, a medical source from the city hospital said.

In Baghdad, four policemen were wounded in a roadside bomb explosion near their patrol in Doura district in the southern part of the Iraqi capital, an interior ministry source said.

In Iraq's eastern province of Diyala, a car bomb went off at a residential area in Jurf al-Milih suburb near the provincial capital city of Baquba, some 65 km northeast of Baghdad, leaving three people killed, including two children, and 19 people wounded, along with damaging six houses, a provincial police source said.

Meanwhile, three gunmen believed to be linked to ISIL were killed in a clash with Iraqi security forces near the city of Udheim, some 60 km north of Baquba, the source said.

In addition, a member of a government-backed Sahwa paramilitary group was shot dead by gunmen at a village near Baquba, the source added.

The violence came just 18 days ahead of the landmark parliamentary elections on April 30, which is the first in the country since the withdrawal of U.S. troops in late 2011.