Thirteen people were killed and eight others wounded in separate attacks across Iraq on Saturday, police and medical sources said.

In Iraq's western province of Anbar, gunmen attacked a police checkpoint in the southwestern part of the provincial capital city of Ramadi, some 110 km west of Baghdad, leaving five policemen and a shovel driver killed at the site.

In a separate incident, an army commando force clashed with gunmen, said to be linked to al-Qaida organization, in the southern city of Fallujah, some 50 km west of the Iraqi capital Baghdad, killing four gunmen and destroying a truck carrying heavy machine gun.

In the meantime, gunmen blew up bombs in two houses belonging to two police officers in the town of Garma, near Fallujah damaging the houses without casualties.

Elsewhere, a government employee was wounded when a sticky bomb attached to his car detonated in the city of al-Qaim, some 330 km northwest of Baghdad.

Also in Anbar, artillery and mortar shelling on several neighborhoods in the militant-seized city during the day left a civilian killed and seven others injured.

Anbar province has been the scene of fierce clashes that flared up after Iraqi police dismantled an anti-government protest site outside Ramadi in late December last year.

In Iraq's eastern province of Diyala, a government-backed paramilitary group member and a civilian were killed in two attacks by gunmen in the city of Maqdadiyah, some 100 km northeast of Baghdad.

The Sahwa militia, also known as the Awakening Council or the Sons of Iraq, consists of armed groups, including some powerful anti-US Sunni insurgent groups. They turned their rifles against the al-Qaida network after the latter exercised indiscriminate killings against both Shiite and Sunni Muslim communities.

Iraq is witnessing its worst violence in recent years. According to the UN Assistance Mission for Iraq, a total of 8,868 Iraqis, including 7,818 civilians and civilian police personnel, were killed in 2013, the highest annual death toll in years.