More than 2,500 people were killed in Iraq in the past three months, UN figures showed on Monday, a surge of violence that has fanned fears the politically-deadlocked country is slipping back into all-out bloodshed.

The toll comes as the country grapples with months of protests among the Sunni Arab minority, tensions in a swathe of territory in northern Iraq disputed by the Kurds, and a protracted political deadlock that has blocked key legislation.

The violence showed no signs of letting up on Monday as new attacks, including a suicide bombing, killed 19 people.

The UN mission in Iraq said a total of 761 people were killed across the country in June, bringing the overall death toll for the past three months to 2,518.

Most of those killed in June were civilians and a further 1,771 were wounded as a result of violence.

Figures compiled by AFP, meanwhile, showed 452 people were killed by violence in June, bringing the total death toll since April to 1,527 -- or twice as many as those killed in the first three months of the year.

Attacks in June targeted a wide cross-section of Iraqi society -- government targets and security forces were hit by car bombs, mosques were struck by suicide attackers, anti-Qaeda militiamen were shot dead, and Iraqis watching and playing football were killed by blasts.

"They (militants) are intent on causing large number of casualties, to embarrass the government, to raise frustrations and possibly stoke a return to militias again," said John Drake, a Britain-based analyst for risk consultancy AKE Group.

"There's something about this period that's very familiar. It feels like we've gone back several years.

"I remember saying the same things in 2007," he added, referring to the brutal sectarian war that blighted Iraq in 2006 and 2007, leaving tens of thousands dead.

The UN and AFP figures were markedly higher than those compiled by government ministries, which pegged last month's toll at 240 dead and 379 wounded.

Casualty figures compiled by the Iraqi government have typically been lower than those tallied by the United Nations, AFP and Britain-based NGO Iraq Body Count.

Iraq Body Count figures for June were not immediately available.

The surge in violence comes amid a protracted political standoff within Iraq's national unity government, with little in the way of landmark legislation passed since a 2010 parliamentary election.

And while political leaders have pledged to resolve the dispute, with Prime Minister Nuri al-Maliki meeting his two main rivals last month in a bid to ease tensions, no tangible measures have been agreed.

Meanwhile, tensions have persisted in a swathe of territory in northern Iraq that Kurdish leaders want to incorporate into their autonomous three-province region over Baghdad's objections.

And months of protests among the Sunni Arab community have continued unabated.

Analysts and diplomats worry that the multi-faceted standoffs are unlikely to see any long-term resolution before a general election due next year.

At the same time, violence has shown no sign of slowing.

On Monday, eight former Sunni tribal militiamen were kidnapped from their homes north of Baghdad in pre-dawn raids by gunmen wearing military uniforms before being shot dead, assassination-style.

The men were all former fighters in the Sahwa, a collection of Sunni tribal militias that turned against Al-Qaeda and sided with the US military from late 2006 onwards, helping turn the tide of Iraq's bloody insurgency.

Later in the day, two separate bombings killed 11 people in confessionally divided Diyala province.

In one, a suicide bomber blew himself up at a Shiite funeral, killing six people, while a blast at a cafe in a Shiite neighbourhood of provincial capital Baquba killed five.

No group immediately claimed responsibility for Monday's violence, but Sunni militants linked to Al-Qaeda frequently target the Sahwa, whom they regard as traitors, and Shiite Muslims, whom they see as apostates.