President Bush and British Prime Minister Tony Blair, each facing pressure to pull back from a long, unpopular war, are gauging the ability of Iraq's new government to shoulder a bigger role. But Bush's spokesman said Thursday the two leaders are not about to declare, "We're all coming home."

Blair flew to Washington for talks Thursday evening and Friday with Bush. The prime minister was reporting on his discussions in Baghdad Monday with Iraq's new prime minister, Nouri al-Maliki, who said his forces are capable of taking control of security in all Iraqi provinces within 18 months. Bush and Blair planned to discuss whether al-Maliki's assertion was realistic.

"We'll see if he's able to follow through on it," White House press secretary Tony Snow said. "It's an interesting question."

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With casualties rising and violence rampant, Iraq weighs heavily on Bush and Blair. Both leaders have plunged in the polls and face growing calls for major troop withdrawals. Bush is under additional pressure from fellow Republicans who are nervous about losing control of the House or Senate — or both — in the November elections.

A showdown with Iran over its suspected nuclear-weapons program also was high on the agenda for Bush and Blair. The two leaders also were expected to discuss fading Mideast peace prospects.

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The United States has about 131,000 troops in Iraq; officials have said they would like to have about 100,000 by year's end. Britain has about 8,000. At least 2,460 members of the U.S. military have died since the beginning of the war. Britain has lost 106 service personnel.

The White House dampened expectations of troop reductions in Iraq or specific dates for cutbacks coming out of the Bush-Blair meeting.

"You know, there aren't going to be people kissing in Times Square tomorrow. But I do think what you will have is a very forward-leaning set of discussions about how to proceed forward," Snow said.

Bush has described the formation of Iraq's new government of Shiites, Sunni Arabs and Kurds as a turning point. But it's unclear what that means in terms of the need for U.S. troops. Pentagon officials are worried about the reliability of U.S.-trained Iraqi police and their religious and tribal allegiances.

Gen. Peter Schoomaker, the Army chief of staff, said his service is planning for the possibility of having to maintain current troop levels in Iraq for the next two years, while also anticipating the possibility of cuts.

Of the 131,000 U.S. troops in Iraq, about 105,000 to 110,000 are Army soldiers.

Schoomaker, in remarks to a group of reporters on Thursday, said Army planners are looking 18 to 24 months into the future to determine how they can provide the number and types of troops required in Iraq.

"We're continuing to plan for a variety of troop levels," he said. "Obviously we're planning to be able to sustain the levels that we have today, but we're running alternatives as well, in anticipation that we'll be asked to do some different levels."

Eager to look in charge, Iraq's new leaders are publicly pressing for Bush and Blair to move toward troop withdrawals while privately seeking assurances from U.S. diplomats and military leaders that the troops won't leave prematurely.

Blair planned to raise with Bush Iraqi plans for an international conference to back its government British officials said.

British officials have said most coalition troops could be withdrawn by 2010, but no timetable is to be agreed upon during the talks, Blair's Downing Street office said.

"What we need is a situation where, if the conditions are right, we can pull back our troops and then withdraw them. That conditions-based approach will guide everything we do," Blair's spokesman said.

Snow said Iraq's new government "creates new opportunities; it really changes things, because now you have people with whom you're going to deal on a regular, daily, and for the foreseeable future, a permanent basis until you have changes of government there, to deal with all of the key issues, not only political, but also military.