Attacks in Iraq -- including twin suicide blasts against an army base and a car bomb targeting Shiite Muslims -- killed 30 people Thursday, a week ahead of a major Shiite pilgrimage.

The bloodshed follows the start of the Islamic new year just days earlier and as Shiite Muslims converge on the shrine city of Karbala, south of Baghdad, for commemoration ceremonies, a period during which Sunni militants often try to target Shiites and the security forces.

It is the latest in Iraq's worst violence since 2008, with more than 5,500 people dead this year despite tightened security measures and a swathe of operations against militants.

Thursday's deadliest violence saw 16 people killed just north of Baghdad.

A suicide bomber blew up a vehicle rigged with explosives at the entrance of an army base just north of Baghdad during the evening, before another suicide car bomber managed to enter the compound and blow himself up.

Overall, at least 16 people were killed and 39 others wounded in the twin explosions in Tarmiyah, a predominantly Sunni Arab town which lies 45 kilometres (30 miles) north of the capital.

Also on Thursday, a car bomb in the predominantly-Shiite neighbourhood of Baghdad Jadida, in the capital's east, killed at least three people and wounded nine others, police and medical officials said.

The explosion caused massive damage to nearby houses and shops. Security forces barred journalists from taking photographs or video, an AFP reporter at the scene said.

The blast comes as pilgrims take part in Ashura commemorations, due to peak on November 14 to mark the death of Imam Hussein, grandson of the Prophet Mohammed who was killed in 680 AD by the armies of the caliph Yazid.

His death has become a formative event in Islam, marking the symbolic split between the Sunni and Shiite sects.

No group immediately claimed responsibility for the bloodshed, but Sunni militants frequently attack Shiites, whom they regard as apostates, during Ashura and the subsequent commemorations of Arbaeen.

Meanwhile in Baghdad's southern outskirts, a bomb in a busy street killed at least one person and wounded four others on Thursday, officials said.

And a suicide bomber detonated a vehicle rigged with explosives at the entrance to an army base in the predominantly Sunni province of Anbar, killing three soldiers and wounding six others.

Police arrested a militant filming the blast in the aftermath of the attack.

Seven other people were killed in attacks north of the capital.

In the main northern city of Mosul, three people were killed in a bombing, while a shooting left an off-duty policeman dead. A roadside bombing in Balad, meanwhile, killed three.

In addition to major security problems, the government has failed to provide adequate basic services such as electricity and clean water, and corruption is widespread.

Political squabbling has paralysed the government, while parliament has passed almost no major legislation in years.