Separate bombings in and around Baghdad have killed at least 14 people, officials say, as authorities tighten security measures in the capital before a major Shia religious event that draws thousands of pilgrims.

The deadliest attack took place in the town of Tarmiyah on Sunday when a car bomber struck a police and army checkpoint, killing five security force members and wounding 10, a police officer said.

The town is about 50km north of Baghdad.

Another car bomb killed three civilians and wounded eight at an outdoor market in Taji, about 20km north of Baghdad, the officer said.

Distrust hangs over Anbar refugees in Baghdad

In the capital's southern Abu Disher neighbourhood, a bomb targeted Shia pilgrims, killing two and wounding seven.

Another civilian was killed and five wounded in a bomb attack in an outdoor market in the northern Baghdad district of Shaab, police said.

The commemoration of the 8th-century Imam Mousa al-Kazim's death draws tens of thousands of Shia from all walks to converge on his golden-domed shrine in northern Baghdad.

The pilgrims typically march to the shrine while hundreds of tents are erected to offer them free food, drinks and services.

Also on Sunday, a suicide bomber drove an explosives-laden armoured military vehicle into a group of government forces during clashes outside the ISIL-held city of Fallujah.

The attack killed at least three soldiers and wounded seven, an army officer said.

Islamic State of Iraq and the Levant, which controls vast areas of northern and western Iraq, claimed responsibility for the attack in an online statement posted on a website.

Source: Agencies