Up to 26 people were killed and 87 others wounded in violent attacks across Iraq on Wednesday, including a series of car bombs in Baghdad, police said.

On Wednesday morning, six car bombs and two roadside bombs detonated almost simultaneously in several districts across the Iraqi capital of Baghdad, leaving at least seven people killed and 64 wounded.

In one of Baghdad attacks, a car bomb went off in Camp Sarah district near the University of Technology in east Baghdad, leaving one person killed and nine others wounded.

Another car bomb ripped through a nearby busy intersection in the same district, killing one and wounding three others.

And two people were killed and eight injured in a car bomb explosion in Shaab district in northeastern part of Baghdad. Another car bomb struck Baghdad's southeastern district of Zaafaraniyah, wounding nine people.

A car bomb hit Shula district in northwestern Baghdad, killing a civilian and wounding 12, while a civilian was killed and six others were injured in a sixth car bomb explosion in Sadr City district in eastern the capital, the source added.

A roadside bomb detonated at a busy intersection in Sadr City district, leaving a civilian killed and seven wounded. Another roadside bomb exploded in Baiyaa district in southern Baghdad and wounded 10 people, he said.

In Iraq's western province of Anbar, a suicide bomber drove his explosive-laden car into an army checkpoint in Albu-Alwan area, in north of the militant-seized city of Fallujah, some 50 km west of Baghdad, leaving seven soldiers killed and four others injured, a provincial police source anonymously told Xinhua.

In Fallujah, the Iraqi army pounded the city with mortar rounds during the day, killing one person and wounding eight others, the source said.

Meanwhile, Iraqi army helicopters pounded a suspected vehicle outside the town of Amriyat al-Fallujah, near Fallujah and killed two people and wounded two others, including a woman, the source added.

In a separate incident, a suicide bomber rammed his explosive- laden car into a police commando checkpoint in the center of the provincial capital city of Ramadi, some 110 km west of Baghdad, killing three commandos and wounding four others, he said.

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, an Indian national was killed and four others were wounded when a roadside bomb struck their vehicle near the provincial capital city of Baquba, some 65 km northeast of Baghdad, a provincial police told Xinhua on condition of anonymity.

Two of the injured Indian nationals were in a critical condition. They were on their way travelling from Baghdad heading to the northern region of Kurdistan, the source said.

Separately, gunmen attacked a police outpost in Imam Weis area, some 50 km north of Baquba, killing a policeman, the source added.

A civilian was killed and another injured by a roadside bomb explosion near their house in Maqdadiyah, some 100 km northeast of Baghdad, while another civilian was killed by gunmen near Baquba, the source said.

Also in the province, the police found the bodies of two people riddled with bullets, one near Maqdadiyah and the other outside Baquba, the source said.

No group has so far claimed responsibility for the deadly attacks, but the al-Qaida front in Iraq, in most cases, were allegedly responsible for such massive attacks in the country, raising fears that the terrorist group and other militia could return to widespread violence.

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 police personnel, were killed in 2013, the highest annual death toll in years.