US Defense Secretary nominee Robert Gates has told a Senate committee that the US is not winning the war in Iraq
Mr Gates told a confirmation hearing he was open to new ideas on Iraq, but warned the situation there would shape the Middle East for years to come.
He is set to be confirmed to replace Donald Rumsfeld, who quit last month amid criticism of his Iraq policy.
The next chairman of the committee said Mr Gates would face a "monumental challenge" in Iraq if he got the job.
Senate hearings on Mr Gates's nomination began a day before the Iraq Study Group - of which Mr Gates was a member - publishes its findings.
The session also came on another violent day in Iraq.
More than 30 people were killed in shootings and car bomb attacks in Baghdad, Iraqi officials said. At least 30 more died in violence in northern and south-western Iraq.
Mr Gates told the Senate Armed Services Committee that all options remained on the table for Iraq.
He agreed with the panel that the situation was unacceptable and said he would introduce a change of tactics, if confirmed.
Mr Gates said he would do his utmost to avoid chaos in Iraq.
"Our course over the next year or two will determine whether the American and Iraqi people and the next president of the US will face a slowly but steadily improving situation in Iraq or... the very real risk and possible reality of a regional conflagration," he said.
Asked by the next chairman of the panel, Democratic Senator Carl Levin, if he believed the US was winning, Mr Gates replied: "No, Sir."
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