More than 70 people were killed in a series of car bombings and suicide attacks targeting Shia Muslims across Iraq today.

The attacks increased the number killed in sectarian clashes in the past week to more than 200.

Tensions between Shias, who now lead Iraq, and minority Sunni Muslims have reached a point where some fear a return to all-out civil conflict.

No group claimed responsibility for the bombings.

Iraq has a number of Sunni Islamist insurgent groups, including the al-Qaeda-affiliated Islamic State of Iraq, which has targeted Shias in a bid to kindle wider sectarian conflict.

Nine people were killed in one of two car bombings in Basra, a predominantly Shia city 420km southeast of Baghdad, police and medics said.

Five other people were killed in a second blast inside a bus terminal in Saad Square in Basra, police and medics said.

In Baghdad, at least 30 people were killed by car bombs in Kamaliya, Ilaam, Diyala Bridge, al-Shurta, Shula, Zaafaraniya and Sadr City - all areas with a high concentration of Shias.

A parked car bomb also exploded in the mainly Shia district of Shaab in northern Baghdad, killing 12 people and wounding 26 others, police and hospital sources said.

In Balad, 80km north of Baghdad, a parked car blew up near a bus carrying Shia pilgrims from Iran, killing five Iranian pilgrims and two Iraqis who were travelling to the Shia holy city of Samarra, police said.

Eleven people were killed by a car bomb and a suicide bomber in Hilla, 100km south of Baghdad, police and medics said.

Both attacks occurred near a Shia place of worship and an outdoor market.

In the western province of Anbar, the bodies of 14 people kidnapped on Saturday, including six policemen, were found dumped in the desert with bullet wounds to the head and chest, police and security sources said.

When Sunni-Shia bloodshed was at its height in 2006-07, Anbar was in the grip of al-Qaeda's Iraqi wing, which has regained strength in recent months.

In 2007, Anbar's Sunni tribes banded together with US troops and helped subdue al-Qaeda.

Known as the "Sahwa" or Awakening militia, they are now on the government payroll and are often targeted by Sunni militants as punishment for co-operating with the Shia-led government.

Three Sahwa members were killed in a car bomb explosion as they collected their salaries in the city of Samarra, north of Baghdad, police said.

A suicide bomber wearing an explosive belt detonated himself at a Sahwa checkpoint, killing two fighters and wounded another seven in Baiji, 180km north of Baghdad.