Gates said the political tumult in Washington over financing the military presence in Iraq shows that both the American public and the Bush administration are running out of patience with the war. He was speaking to reporters in Israel just before his quick flight to Baghdad.

"I would like to see faster progress," he said, adding that momentum by the Iraqi government on political reconciliation as well as legislation on sharing oil revenue would "begin the process to send a message that the leaders are beginning to work together."

He said that, in turn, would create an environment in which violence could be reduced.

Underscoring the urgency in controlling the violence, police said a suicide car bomber rammed into a fuel truck in central Baghdad only hours before Gates' arrival, killing at least 11 people. The attack came a day after one of the bloodiest days in Baghdad since the U.S. troop increase began nine weeks ago, with four strikes killing more than 180 people.

"It is very important they make every effort to get this done as soon as possible," Gates said, noting that an attack last week by a suicide bomber on a cafeteria at the Iraqi parliament inside the U.S.-guarded Green Zone made people particularly nervous.

Gates flew by helicopter to Fallujah for a briefing by Gen. David Petraeus, the commander of U.S. forces in Iraq, and Gen. Peter Pace, the Joint Chiefs chairman. Fallujah is a stronghold for Sunni insurgents.

He also planned to meet with Iraqi political leaders.

His visit, the third to Iraq since taking over as defense secretary in December, came a day after Bush meet congressional leaders to discuss the impasse over legislation to provide funds for the war effort in Iraq and Afghanistan.

Gates said he has had no discussions with the White House about an absolute deadline by which the Pentagon must get additional funding to be able to maintain the mission.

Three of the five brigades ordered into the country by President Bush to stem Baghdad violence have arrived in Iraq, bringing the force in the country to 146,000. Officials want the rest in place by June, for a total of 160,000.

Soon after that they plan to assess how much longer the higher troop level — about 30,000 more than before the buildup — will be needed.

Officials have struggled to find troops from within the stretched U.S. military to sustain the increase. Gates last week took the difficult step of lengthening tours of duty to the war zones in Iraq and Afghanistan to 15 months from a year.

During an hourlong meeting Wednesday at the White House, the president told lawmakers directly he will not sign any bill that includes a timetable for a troop withdrawal, and they made it clear Congress will send him one anyway.

"We believe he must search his soul, his conscience and find out what is the right thing for the American people," Senate Majority Leader Harry Reid of Nevada, told reporters after the session. "I believe signing this bill will do that."

But White House spokeswoman Dana Perino said, "It appears that they are determined to send a bill to the president that he won't accept. They fundamentally disagree."

Democrats hope to complete work on a House-Senate compromise in time to send it to the White House by the end of next week, with Bush's veto a certainty.

Given the narrow Democratic majority in the Senate, it appears unlikely the compromise will include a mandatory date for a complete withdrawal.