WASHINGTON (AFP) – US spy agencies have given a grim assessment of Iraq’s future, warning that the leadership is unable to govern effectively and a drawdown of US forces could increase sectarian violence.

The new intelligence estimate released Thursday also predicted that security improvements made over the past six months will erode if the US military narrows its mission to supporting Iraqi security forces and fighting Al-Qaeda.

The update, which represents the consensus of 16 US intelligence agencies, comes just weeks before General David Petraeus, the US commander in Iraq, and US Ambassador Ryan Crocker offer their own assessment of US strategy in a report due on September 15.

The US intelligence community “assesses that the Iraqi government will become more precarious over the next six to 12 months because of criticism by other members of the major Shia coalition” as well as Sunni and Kurdish parties, the new estimate warned.

Barring “a fundamental shift in factors driving Iraqi political and security developments,” compromises needed for “sustained security, long-term political progress, and economic development are unlikely to emerge,” the assessment said.

The declassified judgments of the assessment were released by the office of the Director for National Intelligence Mike McConnell, and came amid mounting US frustration over the lack of political progress in Iraq.

Attempts by Iraqi Prime Minister Nuri al-Maliki to bridge Iraq’s ethnic and sectarian divides have so far failed. Seventeen members of his 40-person cabinet have resigned, and the daily bloodshed takes a stiff toll on ordinary Iraqis.

Iraqi leaders who are already “unable to govern effectively” will struggle to achieve national political reconciliation, it warned.

Since its January assessment there have been “measurable but uneven” improvements in Iraq’s security, the report said, adding however that the “level of overall violence, including attacks on and casualties among civilians, remains high.”

Earlier in the year US President George W. Bush ordered 30,000 more troops to Iraq — boosting US forces on the ground to 160,000 — in a bid to improve security.

Iraqi security forces have performed adequately, but have not improved enough to conduct major operations independent from US-led coalition forces, the report said.

Changing the coalition’s mission to focus on providing combat support for Iraq’s security forces and fighting Al-Qaeda “would erode security gains achieved thus far,” it warned.

The conclusions could be used by the Bush administration to justify prolonging the surge, despite growing domestic opposition to the war and calls for a troop drawdown.

The White House said the assessment shows that US strategy “has improved the security environment in Iraq, but we still face very tough challenges ahead.”

“This is a government that is learning, frankly, learning how to govern. And, no, it is not moving nearly as fast as everyone in Washington would like it to move,” said spokesman Gordon Johndroe, reiterating support for the government “because they are trying right now in Baghdad to move forward.”

Just hours after the assessment came out influential Republican Senator John Warner urged Bush to start a limited withdrawal of US troops from Iraq by Christmas.

The move would send a signal the Maliki administration and regional nations that the US commitment to Iraq is not open-ended, said Warner, who returned recently from Iraq.

“Certainly in 160,000-plus (US troops in Iraq), say, 5,000 could begin to redeploy and be home to their families and loved ones no later than Christmas of this year,” he said.

The United States “simply cannot, as a nation, stand and put our troops at continuous risk of loss of life and limb without beginning to take some decisive action which will get everybody’s attention,” Warner said.

He added: “I really firmly believe the Iraqi government, under the leadership of Prime Minister Maliki, have let our troops down.”

The intelligence report said that perceptions of a US pullout “probably will encourage factions anticipating a power vacuum to seek local security solutions that could intensify sectarian violence and intra-sectarian competition.

Maliki has so far failed to deliver any major pieces of legislation aimed at promoting reconciliation between Sunnis and Shiites.

Bush this week expressed his frustration with the lack of progress, only to reaffirm his support for Maliki the following day, calling him a “good man with a difficult job.”