AMMAN, Jordan, Nov. 30 — President Bush said Thursday that American troops would stay in Iraq unless its government asks them to leave, using a joint news conference with the Iraqi prime minister to push back against a reported decision by an independent bipartisan panel to call for a gradual withdrawal.

"I know there’s a lot of speculation that these reports in Washington mean there’s going to be some kind of graceful exit out of Iraq,” Mr. Bush said during a joint news conference in Amman with Prime Minister Nuri Kamal al-Maliki, referring to the final report by the Iraq Study Group that is expected next week. “We’re going to stay in Iraq to get the job done so long as the government wants us there.”

The president, who returned to Washington later on Thursday, sought to play down tensions between him and Mr. Maliki, calling the prime minister “the right guy for Iraq.”

Mr. Bush also said he and Mr. Maliki would oppose any plan to partition the country, which is increasingly divided by sectarian violence. The two appeared together after an hourlong breakfast meeting with aides at the Four Seasons Hotel here that was followed by a 45-minute one-on-one session.

“The prime minister made clear that splitting his country into parts, as some have suggested, is not what the Iraqi people want, and that any partition in Iraq would only lead to an increase of sectarian violence,” Mr. Bush said, adding, “I agree.”

The two leaders set no timetable for speeding up the training of Iraqi forces, which Mr. Bush described as evolving “from ground zero,” and a senior administration official, who attended the breakfast and was granted anonymity to discuss it, said hurdles remain.

“This is not a simple process of passing the baton,” the official said, adding, “This is not the United States and Iraq struggling for control of the steering wheel. This is the United States wanting Iraq to be firmly with the steering wheel in its hand, and the issue is, how do we get there as quickly as possible.”

Mr. Maliki later asserted that his country’s police and military forces would be ready to take over responsibility for Iraq’s security next year. “I cannot answer on behalf of the U.S. administration but I can tell you that from our side our forces will be ready by June 2007,” he told ABC News.

In Baghdad on Thursday, the pressures on Mr. Maliki continued to grow. An aide to Moktada al-Sadr, the anti-American Shiite cleric whose followers have boycotting the Iraqi Parliament, to protest Mr. Maliki’s meeting with Mr. Bush, announced an effort to form a political alliance across ethnic and religious lines to push for a timetable for the withdrawal of American troops.

And in a reminder of the security challenge facing the country, the American military announced that Iraqi forces had discovered a mass grave containing 28 bodies near the troubled city of Baqubah and that an American soldier had died in combat in Baghdad on Wednesday.

Tensions have been rising between Mr. Bush and Mr. Maliki. On Wednesday evening, Mr. Maliki took the unusual step of backing out of a planned meeting with the president, an embarrassment to the White House that came on the heels of the publication of a classified memo from National Security Adviser Stephen J. Hadley that raised doubts about Mr. Maliki’s leadership.

On Thursday, both men tried to tamp down any suggestion that the relationship was strained. Mr. Bush said yet again that he had confidence in the Iraqi prime minister.

“I’ve been able to watch a leader emerge,” the president said, describing the threats Mr. Maliki said he had received since becoming prime minister, including shells being fired at his house.

Mr. Bush added, “You can’t lead unless you’ve got courage. He’s got courage and he’s shown courage over the last six months.”

Mr. Maliki, for his part, dismissed any suggestion that he had canceled Wednesday’s meeting out of pique, saying the meeting — which had been scheduled to include King Abdullah II of Jordan — was not necessary because the prime minister and the king had already had discussion earlier in the day. “So there’s no problem,” Mr. Maliki said.

The senior official said the Hadley memo did not come up during the breakfast, except for a few jokes about leaks to the news media — a reference to The New York Times, which published the memo on Wednesday. The official said Mr. Bush and Mr. Maliki seemed comfortable with one another.

“There’s no cloud over the meeting in any fashion whatsoever,” she said.

Still, tensions seemed to bubble just under the surface. The two leaders barely looked at one another during the news conference. And when Mr. Bush, at one point, asked the prime minister if he wanted to continue taking questions from reporters, the prime minister swiveled his head toward the president and shot Mr. Bush an incredulous look.

The high-profile summit meeting and news conference underscored just how much pressure each man is facing to make changes in his relationship with the other.

In Mr. Bush’s case, that pressure is coming both from the Democrats about to take control of Congress, who want a withdrawal of troops, and the Iraq Study Group led by former Secretary of State James Baker, which is expected to deliver a report next week that calls for a gradual troop withdrawal, without a specific timetable for pulling out.

In Mr. Maliki’s case, the pressure is coming from Mr. Sadr, the Shiite cleric provides crucial political support to the prime minister. White House advisers want Mr. Maliki to reduce his reliance on the Sadr faction, but Mr. Maliki on Thursday sidestepped a question about whether, or how, he would do so.

"My coalition is not only with one entity,” the prime minister said, speaking through an interpreter. He added, “Mr. Sadr and the Sadrists are just one component that participate in the parliament.”

At a news conference in Baghdad on Thursday following his return from Amman, Mr. Maliki called for an end to the parliamentary boycott by legislators and cabinet members loyal to Mr. Sadr.

"I wish they would reconsider their decision because it doesn’t represent a positive development in our political process," he said.

The members of Mr. Sadr’s bloc said they would end their boycott on condition that Mr. Bush cede more authority over Iraqi security forces to Mr. Maliki, and that the government improve public services. The first condition seemed to be met at the meeting in Amman.

A member of Parliament who plays a prominent role in Mr. Sadr’s bloc, Falah Hassan Shenseh, said Thursday that efforts had begun to form “a front for the anti-American-occupation” point of view, with a goal of forcing the United States to set a timetable for withdrawal.

Mr. Shenseh said the group would cut across sectarian lines. “It’s a patriotic national group,” he said. “We need to be freed from occupation.”

Mr. Shenseh declined to say when the walkout by cabinet ministers and members of Parliament aligned with Mr. Sadr would end, but another prominent Shiite politician said Thursday that he expected them to return in about a week.

In Moscow on Thursday, a Russian official called for a large international conference to be convened, possibly under the auspices of the United Nations, to come up with a plan to halt Iraq’s slide into chaos.

“The situation is getting worse,” said Anatoli, Safonov, an aide to President Vladimir V. Putin, according to Agence France-Presse.

But in Amman, Mr. Bush steered away from suggestions of a rapid change of course. Neither he nor Mr. Maliki said anything specifically how they intended to speed the transfer of responsibility for security from American to Iraqi forces, and they did not announce any milestones or set goals by which to measure progress.

“As soon as possible,” Mr. Bush said, when asked how quickly he expected the transfer to occur.

“I’ve been asked about timetables ever since we got into this. All the timetables mean is a timetable for withdrawal,” he went on. “All that does is set people up for unrealistic expectations.”