WASHINGTON (AFP) – Violent attacks in Iraq have soared to the highest level on record, the Pentagon said in a quarterly report, describing Moqtada al-Sadr’s Mahdi Army militia as the single largest threat to stability.

The report, released just hours after former CIA chief Robert Gates was sworn in Monday as the new defense secretary, said there was an average of 959 attacks per week between August 12 and November 10.

That is the highest recorded level of attacks since the US Congress ordered the Pentagon in 2005 to compile and issue the quarterly data.

There was a 22 percent jump in attacks and a two percent increase in civilian casualties compared to the three preceding months said the report, titled “Measuring Stability and Security in Iraq.”

Sixty-eight percent of the attacks were aimed at soldiers with the US-led coalition, but most casualties were Iraqis.

“The violence in Iraq poses a grave threat to political progress,” the report said Tuesday, adding that some of the increase “could be attributed to a seasonal spike in violence during (the holy month of) Ramadan.”

Attacks on infrastructure have dropped, but the cumulative effect of attacks have strained services for Iraqis, according to the report.

Fifty-four percent of all attacks took place in the provinces of Baghdad and Al-Anbar. Outside of that area, which encompasses most of what US officials call the Sunni Triangle, “more than 90 percent of Iraqis reported feeling very safe in their neighborhoods,” it said.

The largest threat to security was radical Shiite cleric Sadr’s Mahdi Army militia, “which has replaced Al-Qaeda in Iraq as the most dangerous accelerant of potentially self-sustaining sectarian violence in Iraq,” according to the report.

Sadr’s Iranian-backed militia is believed to have up to 60,000 fighters, and is blamed for much of the violence against minority Sunnis.

The 30-strong Sadrist bloc in Iraq’s parliament is also a key part of Prime Minister Nuri al-Maliki’s ruling coalition.

The Pentagon report said that Iraq’s National Reconciliation and Dialogue Project, aimed at building ties between mainstream Shiite and Sunni political groups and to isolate Iraq’s insurgent groups and illegal militias, had “shown little progress” as sectarian violence “has steadily increased despite meetings among religious and tribal leaders.”

Gates, who announced he would soon travel to Iraq to hear directly from US military commanders, said at his swearing-in ceremony that “failure in Iraq … would be a calamity that would haunt our nation, impair our credibility and endanger Americans for decades to come.”

Debate is currently raging in Washington over whether to send more US troops to Iraq to control violence before handing over security to the Iraqis.

Top US military officials are questioning a White House plan to send between 15,000 and 30,000 more US troops to Iraq for up to eight months, The Washington Post reported Tuesday.

US troop levels in Iraq have dipped to 129,000 over the past week, but have generally hovered around 140,000.

The paper, citing unnamed US officials familiar with the “intense” debate, said the Joint Chiefs of Staff unanimously disagree with the plan, in part because the force’s mission has not been defined.

The Joint Chiefs believe the White House is pushing the plan for more troops partly because of limited alternatives, according to the Post.

The top Pentagon officials have told President George W. Bush that a short-term troop increase could boost virtually all of Iraq’s armed factions without strengthening the long-term position of the US military or Iraq’s security forces, the Post reported.

Plummeting US public support for the Iraq war has spurred the US president to undertake a major Iraq strategy review.

After meeting with US military chiefs last week, Bush said he was putting off a decision on the way forward until early January.