BAGHDAD: Attacks north of Baghdad, including a third suicide blast in as many days, killed at least eight people Tuesday, officials said, amid a spike in violence that has left almost 70 people dead in all.

The latest bloodshed, in which over 150 people have been wounded, has raised tensions as Iraq grapples with a political crisis and demonstrators in mostly Sunni areas of the country call for the resignation of the Shiite premier.

In Tuesday's deadliest attack, six people, including three soldiers, were killed in a suicide car bombing in the town of Taji, just north of the capital, security and medical officials said.

Fourteen others were wounded in the explosion, which targeted a joint army-police patrol near a prison.

Also on Tuesday, shootings and bombings in the restive cities of Baquba and Mosul left two people dead.

The latest attacks took the overall toll from three days of violence in Baghdad and north of the capital to at least 68 dead and 152 wounded, according to an AFP tally.

On Monday, a suicide bomber blew himself up amid a group of anti-Qaeda militiamen collecting their salaries in Taji, killing 23 people and wounding dozens more.

The previously day, another suicide car bomb followed by an assault carried out by grenade-throwing gunmen on a police headquarters in north Iraq killed 30 people.

No organisation has claimed responsibility for the deadly string of attacks, but Sunni militants including Al-Qaeda's front group often target security forces and government targets in a bid to destabilise the country and push it back to the sectarian war that blighted Iraq from 2005 to 2008.

The latest violence comes amid a political crisis pitting Prime Minister Nuri al-Maliki against his government partners as weeks of demonstrations have raged in Iraq's north and west calling for the premier's ouster.