A series of attacks in Iraq has left at least 24 Shiites and five policeman dead.

The violence has been blamed on insurgents trying to enflame the country's renewed sectarian tensions.

In one of the attacks on Shiites, a suicide bomber rammed his explosives-laden motorcycle into a funeral tent for a family in the town of in Muqdadiyah, about 90 kilometre north of Baghdad, officials said.

The explosion late last night killed 13 people and wounded 24.

In the northern town of Dujail, about 80 kms from Baghdad, a parked car bomb went off outside a Shiite mosque. As people gathered around the blast site, another bomb went off.

The twin bombing killed at least 11 people and wounded 25, said the town mayor.

The two attacks raised the overall death toll yesterday from a series of attacks, which included assaults on police stations in the cities of Ramadi and Fallujah west of Baghdad, to 40.

Sunni cleric Salah al-Nuaimi urged calm among Iraqis during a joint Sunni-Shiite Friday sermon in Baghdad aimed at easing sectarian tensions.

"Enough is enough," al-Nuaimi told worshippers at a Baghdad mosque. "We all love Iraq, we are all Iraqis and we want to be united, we want to stop the bloodletting, develop and build Iraq.

"Stop fighting, we have had enough of bombings. We want to agree on one word, we want to worship inside mosques comfortably," he added.

But attacks continued today. A suicide car bomber struck a police patrol outside the northern city of Mosul, killing four policemen.

And outside the northern city of Tikrit, 130 kms north of Baghdad, drive-by shooters armed with pistols fitted with silencers killed a senior police officer.

The killings are the latest in a wave of bloodshed that has claimed the lives of more than 2,600 people since the start of April.

The months-long eruption of violence - Iraq's worst in half a decade - is raising fears the country is again returning to the brink of a civil war pitting its Sunni and Shiite Muslim sects against one another

There has been no claim of responsibility for the latest attacks but al-Qaida's Iraq branch, which has been gaining strength in recent months, frequently targets Shiites, security forces and civil servants in an effort to undermine the Shiite-led government in Baghdad.

According to the United Nations mission to Iraq, violence in June alone claimed the lives of 761 Iraqis and wounded 1,771 others.