Iraqi officials said Wednesday that U.S. and coalition forces as well as an increase in sectarian violence were behind the surge in civilian casualties cited in a U.N. report.

The report by the U.N. Assistance Mission in Iraq said nearly 6,000 Iraqi civilians were killed in May and June in a wave of assassinations, bombings, kidnappings, torture and intimidation.

However, deputy Prime Minister Salam al-Zubaie blamed U.S. and other coalition forces for much of the violence, saying their troops were responsible for about half the deaths due to "raids, shootings and clashes with insurgents."

CountryWatch: Iraq

"They came to protect the people and democracy and all the problems we have today are because of them. It is a loss for Iraq," said al-Zubaie, a Sunni Muslim.

He also said Iraq's Interior and Defense Ministries had been infiltrated by militiamen who are responsible for many deaths.

Kurdish legislator Mahmoud Othman said the U.N. report makes clear that if the situation continues, "catastrophe will hit the country.."

"The U.N. report is a warning to officials and politicians that the situation is very bad and they have to be careful and solve it but the government cannot find a solution," Othman said.

Sectarian violence increased sharply after the Feb. 22 bombing of a Shiite shrine in Samarra. Since then, thousands of Shiites and Sunnis have been slain.

A Shiite member of parliament, Hassan al-Suneid, blamed the death toll on sectarian tensions and on the failure of the security plan for Baghdad declared by the government of Prime Minister Nouri al-Maliki.

Al-Suneid, a member of the parliament's security committee, also said the June 7 killing of Al Qaeda in Iraq leader Abu Musab al-Zarqawi had made "the terrorists...wild for revenge."

According to the U.N. report, 2,669 civilians were killed in May and 3,149 were killed in June. Those numbers combined two counts: from the Ministry of Health, which records deaths reported by hospitals; and the Medico-Legal Institute in Baghdad, which tallies the unidentified bodies it receives.

The report's figures were higher than some other counts, but even the U.N. said many killings go unreported.

According to an Associated Press tally, at least 1,511 civilians were killed in May and June.