A wave of attacks including six car bombs, nine roadside bombs and a shooting killed 19 people and wounded 71 others on Tuesday in Iraq, security and medical officials said.

The violence was mainly centred in Baghdad, where Shiites were targeted, and the country's north, which has seen high tensions in areas the autonomous Kurdistan wants to incorporate over the strong objections of the federal government.

In north Baghdad, three car bombs exploded near Shiite places of worship, known as husseinyahs, in the Shuala, Graiat and Hurriyah areas, killing at least 12 people and wounding 50, officials said.

Earlier, three car bombs exploded in Kurdish areas of the disputed north Iraq city of Kirkuk, killing four people and wounding 16 others, while two roadside bombs exploded in an Arab-majority town about 50 kilometres (30 miles) east of Kirkuk, killing two people and wounding a third, officials said.

The attacks came a day after federal and Kurdish security chiefs reached an agreement aimed at easing high tensions in disputed northern areas, which Iraq's parliamentary speaker has warned could lead to civil war.

Six roadside bombs targeted the army and police in the disputed town of Tuz Khurmatu, wounding two members of the security forces, police Lieutenant Colonel Khaled al-Bayati said.

And gunmen shot dead an anti-Qaeda Sahwa militiaman near Baquba, while a roadside bomb in the centre of the city wounded two civilians, a police officer and a doctor said.

There was no immediate claim of responsibility for the attacks, but car and roadside bombs are a hallmark of Sunni insurgent groups in Iraq.

Violence in Iraq has decreased dramatically from its peak in 2006 and 2007, when brutal sectarian violence swept the country, but attacks remain common.

According to Iraqi government figures, 144 people were killed and 264 wounded in attacks last month.