After nearly four years of war and the deaths of more than 2,900 U.S. troops, the situation is "grave and deteriorating," the bipartisan panel said. It also warned, "The ability of the United States to influence events within Iraq is diminishing."

It recommended the U.S. reduce political, military or economic support for Iraq if the government in Baghdad cannot make substantial progress toward providing for its own security.

The report said Bush should put aside misgivings and engage Syria, Iran and the leaders of insurgent forces in negotiations on Iraq's future, to begin by year's end. It urged him to revive efforts at a broader Middle East peace. Barring a significant change, it warned of a slide toward chaos.

In a slap at the Pentagon, the commission said there is significant underreporting of the actual level of violence in the country. It also faulted the U.S. intelligence effort, saying the government "still does not understand very well either the insurgency in Iraq or the role of the militias."

On the highly emotional issue of troop withdrawals, the commission warned against either a precipitous pullback or an open-ended commitment to a large deployment.

"Military priorities must change," the report said, toward a goal of training, equipping and advising Iraqi forces. "We should seek to complete the training and equipping mission by the end of the first quarter of 2008."

The commission recommended the number of U.S. troops embedded to train Iraqis should increase dramatically, from 3,000-4,000 currently to 10,000-20,000. Commission member William Perry, defense secretary in the Clinton administration, said those could be drawn from combat brigades already in Iraq.

Bush received the report in an early morning meeting at the White House with commission members. He pledged to treat each proposal seriously and act in a "timely fashion."

The report intensifies pressure on the president to change direction, but he is under no obligation to follow its recommendations. Still to come are options being developed in separate studies by the Pentagon, the State Department and the National Security Council. The White House says he will make decisions within weeks.

"If the president is serious about the need for change in Iraq, he will find Democrats ready to work with him in a bipartisan fashion to find a way to end the war as quickly as possible," said Rep. Nancy Pelosi, the California Democrat who is in line to become speaker when the new Congress convenes in January.

"The president has the ball in his court now ... and we're going to be watching very closely," said Harry Reid, the Nevada Democrat who will take over as Senate majority leader in January.

Rep. John Boehner of Ohio, who will take over as House Republican leader next year, said he was pleased there was no call for a firm deadline for a troop withdrawal. "We will not accomplish victory by setting arbitrary deadlines or negotiating with hostile governments," he said.

Bush was flanked at the White House meeting by the panel's co-chairmen, former Secretary of State James A. Baker III, and former Rep. Lee Hamilton in a remarkable scene — a president praising the work of a group that had just concluded his policy had led to chaos and risked worse.

"Many Americans are understandably dissatisfied," Hamilton said later at a news conference that marked the formal release of the results of the commission's eight-month labors.

"There is no magic bullet," said Baker.

The report painted a grim picture of Iraq nearly four years after U.S. forces toppled Saddam Hussein. It urged Bush to embrace steps he has thus far rejected, including involving Syria and Iran in negotiations over Iraq's future.

It warned that if the situation continues to deteriorate, there is a risk of a "slide toward chaos (that) could trigger the collapse of Iraq's government and a humanitarian catastrophe."

"Neighboring countries could intervene. ... The global standing of the United States could be diminished. Americans could become more polarized," commissioners said.

Baker, Hamilton and the other members of the commission traveled to the Capitol from the White House to present their findings to senior lawmakers. The report makes 79 separate recommendations on Iraq policy.

The recommendations came at a pivotal time, with Bush under domestic pressure to change course and with the new, Democratic-controlled Congress certain to cast a skeptical look at administration policy.

Additionally, Defense Secretary Donald H. Rumsfeld, the architect of the administration's war policy, has resigned. His replacement, Robert Gates, is on track for Senate confirmation this week after a remarkable assessment of his own — that the United States is not winning the war.

Bush has rejected establishing timetables for withdrawing the 140,000 U.S. troops and has said he isn't looking for "some kind of graceful exit out of Iraq."

There was no letup Wednesday in the killing in Iraq, where a mortar attack killed at least eight people and wounded dozens in a secondhand goods market. Police said the shelling was followed closely by a suicide bombing in the Sadr City Shiite district of the capital.

It was the type of violence that has led many to declare that Iraq is in the throes of a civil war — an assessment that Bush has refused to accept.

By whatever name, Baker, Hamilton and the other eight members of the commission said the status quo was unacceptable.

"Violence is increasing in scope and lethality. It is fed by a Sunni Arab insurgency, Shiite militias, death squads, al-Qaida and widespread criminality. Sectarian conflict is the principal challenge to stability," the report said.

The commission's recommendation to have U.S. forces embedded with Iraqi units reflects an approach the military already has been emphasizing in recent months. But administration officials say Iraqis are not yet ready to go it alone against the insurgency.

U.S. allies in the region, including the powerful Sunni leadership in Saudi Arabia, say the Arab-Israeli conflict underlies other Mideast problems and that rancor from the impasse makes other issues harder to solve.

The commission recommended that a "diplomatic offensive" begin by Dec. 31 aimed at building an international consensus for stability in Iraq, and that it include every country in the region.

The United States accuses Syria and Iran of bankrolling terrorism and stirring up trouble in the region. The United States has had no diplomatic ties to Iran for nearly three decades, and pulled its ambassador from Syria last year.

Still, the commission said, "Given the ability of Iran and Syria to influence events within Iraq and their interest in avoiding chaos in Iraq, the United States should try to engage them constructively."

Ahead of the report's release, the White House said it would consider talking to Iran and Syria if the commission recommended it.

The Iraq Study Group report is available at: