Attacks in Iraq killed 22 people on Tuesday, including six shot dead when gunmen stormed a house where a corpse was being ritually washed ahead of a funeral, officials said.

The violence in central and northern Iraq, including an area known as the "Triangle of Death", is the latest in a surge in unrest that has left more than 4,000 people dead so far this year.

Authorities have sought to tackle the country's worst bloodshed since 2008 with wide-ranging operations targeting militants as well as tight traffic measures in the capital, but attacks have continued to rock many cities.

In Tuesday's deadliest violence, gunmen stormed a house in the town of Yusufiyah and killed six people, including two women, as they were ritually cleansing the body of a Sunni Arab man ahead of his funeral, a police officer and a doctor at a nearby hospital said.

Also among the victims was the dead man's son.

Two more people were killed and seven others wounded in the nearby town of Latifiyah by a roadside bombing near a cafe.

Yusufiyah and Latifiyah lie within the confessionally mixed Triangle of Death, south of Baghdad, so called because of the brutal violence in the area at the peak of Iraq's sectarian war in 2006-2007.

Latifiyah in particular has seen a recent spike in bloodletting, including separate early-morning attacks by gunmen on two families.

At Nahrawan in the same region, an explosive device went off near a football field, killing two youths who were playing football.

Elsewhere on Tuesday, three separate car bombs near Baquba, north of Baghdad and capital of restive Diyala province, left 10 people dead and dozens wounded, security and medical officials said.

Baquba, as well as the surrounding province, is mostly populated by Sunni Arabs, albeit with substantial Shiite Muslim and Kurdish minorities. The province remains one of Iraq's least stable.

And in the northern city of Mosul, two people, including a policeman, were gunned down by militants, while three bodies were found in northern Iraq as well.

In a failed attempt to assassinate the governor of northern Salaheddin province, gunmen opened fire on his convoy, wounding five of his guards.

The spike in violence this year has sparked concerns Iraq is slipping back towards the all-out sectarian war that engulfed it in 2006 and 2007.

Officials have vowed to press on with a campaign targeting militants they say has led to the capture of hundreds of fighters and the killing of dozens more, as well as the dismantling of militant training camps and bomb-making sites.

But the government has faced criticism for not doing more to defuse anger in the Sunni Arab community over alleged ill-treatment at the hands of the Shiite-led authorities, which analysts and diplomats say militant groups exploit on the ground to recruit and carry out attacks.

This month, an Al-Qaeda front group claimed responsibility for a spate of car bombs in Baghdad that targeted Shiite neighbourhoods and left 50 dead, and have explicitly said attacks have been carried out in retribution for operations targeting Sunnis and executions of convicted militants.