WASHINGTON – President Bush said America will assist Iraq in a critical operation to regain control of Baghdad and rein in militias that have contributed to the sectarian violence that has swept over the country.

American troops will join with thousands of Iraqi soldiers and police officers to re-establish the rule of law in Iraq’s capital as a step toward putting the new government of Prime Minister Maliki firmly in charge, Mr. Bush said. He also ruled out setting any timetable for withdrawing American troops.

“I sense something different in Iraq,” Mr. Bush said yesterday at a White House news conference after returning form yesterday’s surprise trip to Baghdad. “The progress will be steady toward a goal that has clearly been defined.”

Iraq also must get assistance in rebuilding its economy, including boosting oil production and pressuring other nations to make good on pledges of aid, Mr. Bush said.

The completion of Mr. Maliki’s Cabinet, the killing of Abu Musab al-Zarqawi, and the end of the criminal investigation of top political adviser Karl Rove in the CIA leak case has given Mr. Bush a burst of good news.

A USA Today/Gallup poll this week showed Mr. Bush’s approval rating at 38%, up from an all-time low of 31% in May. The public remains divided on Iraq, with 51% of those questioned in the poll saying going to war was a mistake.

Mr. Bush is seeking to use the positive developments to rebuild support for his Iraq strategy, which has come under criticism from members of both parties in Congress. The president met later yesterday with Democratic and Republican lawmakers at the White House to discuss Iraq.

While in Baghdad, Mr. Bush assured Mr. Maliki and his Cabinet that America won’t reduce its 133,000 troops until the government is firmly established and can secure and defend the country. He also stressed to the Iraqi leaders that the fate of their nation “is in your hands.”

While the development of a democracy in the Middle East will require more “sacrifice and patience,” the American efforts are “well worth it,” he said yesterday. “This is a tough struggle and the reason why is the rules of warfare as we know them are out the window,” Mr. Bush said.

Mr. Bush said he won’t set out a deadline for drawing down some of the 133,000 American troops in Iraq or establish some minimum level of violence that would trigger a withdrawal.

“If we stand down too soon it, won’t enable us to achieve our objectives,” Mr. Bush said.

The president expressed confidence in the ability of Mr. Maliki’s government.

“I saw first-hand the strength of his character and his deep determination to succeed to build a country that can sustain itself, govern itself, and defend itself,” Mr. Bush said.

Mr. Bush repeated his past statement that Iraq should use its oil resources as a tool to unite the country, including establishing a “royalty trust” to benefit the public and making sure that all areas of the country share in the wealth. Iraq has the world’s third largest oil reserves.

Iraq’s oil production was 1.935 million barrels a day in May, according to Bloomberg estimates, down from 2.050 million barrels a day in April and below production levels prior to the 2003 American-led invasion.

Mr. Bush said he directed Treasury Secretary Snow to dispatch an American government team to Iraq to help create a public finance system that is “accountable and transparent” and “I reminded the government that that oil belongs to the Iraqi people.”

The president said the recent suicides of three detainees at the military prison at Guantanamo Bay, Cuba, combined with the abuses of Iraqi prisoners at the Abu Ghraib prison outside of Baghdad have hurt America. Still, he said, the military can’t release the suspected terrorists being held at Guantanamo Bay.

“I’d like to close Guantanamo, but I also recognize that we’re holding some people who are darned dangerous and we better have a way to deal with them in our courts,” he said. “Eventually these people will have trials.”