President Bush will tell the nation Thursday evening that he plans to reduce the American troop presence in Iraq by as many as 30,000 by next summer but will condition those and further cuts on continued progress, The Associated Press has learned.

In a 15-minute address from the White House at 9 p.m. EDT, Bush will endorse the recommendations of his top general and top diplomat in Iraq, following their appearance at two days of hearings in Congress, administration officials said. The White House plans to issue a written status report on the so-called surge on Friday, they said.

The officials spoke on condition of anonymity because Bush's speech is not yet finally drafted. Bush was practicing the speech and putting the final touches on it even as the U.S. commanding general, David Petraeus, and U.S. Ambassador Ryan Crocker were still presenting their arguments on Capitol Hill.

The reductions envisioned by the White House mirror those proposed by Petraeus and would leave approximately 130,000 U.S. troops on the ground by August, roughly the same level that existed before Bush ordered the buildup early this year, the officials said.

In the speech, the president will say he understands the deep concerns Americans have about U.S. involvement in Iraq and their desire to bring the troops home, they said. Bush will say that after hearing from Petraeus and Crocker, he has decided on a way forward that will reduce the number of troops but not abandon Iraq, they said.

The address will stake out a conciliatory tone toward Congress but Bush will place more conditions on the pace of reductions to the pre-buildup level of 130,000 than Petraeus did.

At the White House Tuesday afternoon, Bush met with House and Senate lawmakers of both parties and he publicly pledged to consider their input. "It's very important before I make up mind that I consult with leaders of the House and the Senate," he said.

Bush will also adopt Petraeus' call for more time to determine the timing and scale of withdrawals below the 130,000 mark and offer to report to Congress in March about such plans, one official said.

White House press secretary Tony Snow said Petraeus and Crocker had presented compelling arguments about "what appears to be trend lines that are pointing to success" and that "if you've got something that is succeeding, you want more of it."

He denied, however, that he was offering a preview of what Bush would tell the nation. "Whether the president agrees or disagrees, we're going to find out," Snow told reporters on Tuesday.

Republican support for the Iraq war remains on shaky ground in Congress, epitomized by heated questioning Tuesday by GOP senators of the general's recommendations. But support for the plan hasn't been lost entirely.

Many rank-and-file Republicans say they are deeply uneasy about keeping troops in Iraq through next summer, but they also remain reluctant to embrace legislation ordering troops home by next spring. Democrats had anticipated that a larger number of Republicans by now would have turned against Bush on the war because of grim poll numbers and the upcoming 2008 elections.

If Republican support for the war holds, as it might for now, Democrats would have to soften their approach if they want to pass an anti-war proposal. But they remain under substantial pressure by voters and politically influential anti-war groups to settle for nothing less than ordering troop withdrawals or cutting off money for the war — legislation that has little chances of passing.

Word of Bush's plan spread on a day in which several Republicans on the Senate Foreign Relations Committee sharply questioned Petraeus and Crocker on the Iraq war policy.

"Are we going to continue to invest blood and treasure at the same rate we're doing now? For what?" asked Sen. Chuck Hagel, R-Neb., who supports legislation setting a deadline to bring troops home.

The exchanges came just a day after Petraeus recommended keeping the bulk of U.S. forces in Iraq — some 130,000 troops — deployed there through next summer.

Whereas Republicans were once deferential to the thinking of officials running the war, particularly uniformed officers, Hagel and other GOP senators on the panel said they doubted that simply giving war commanders more time would necessarily yield results.

"In my judgment, some type of success in Iraq is possible, but as policymakers, we should acknowledge that we are facing extraordinarily narrow margins for achieving our goals," said Sen. Richard Lugar of Indiana, the top Republican on the committee.

Sen. Norm Coleman said he appreciates plans to return troop levels to 130,000 — down from the 168,000 currently in Iraq — but that he wants a longer-term vision other than suggestions that Petraeus and Crocker return to Capitol Hill in mid-March to give another assessment.

"Americans want to see light at the end of the tunnel," said Coleman, R-Minn.

Echoing testimony given to the House on Monday, Petraeus and Crocker acknowledged that Iraq remains largely dysfunctional but said violence in recent months had decreased since the influx of the added 30,000 troops deployed earlier this year.

Crocker said he believed Iraq had "almost completely unraveled" in late 2006 and early 2007. The increased security, if given more time, could pave the way for political reconciliation, he said.

The ambassador said he fears that announcing troop withdrawals, as Democrats want, would focus Iraqi attention on "building the walls, stocking ammunition and getting ready for a big nasty street fight" rather than working toward reconciliation.

"I do believe that Iraq's leaders have the will to tackle the country's pressing problems, although it will take longer than we initially anticipated because of the environment and the gravity of the issue," Crocker said.

The stakes are high, he added.

"An Iraq that falls into chaos or civil war will mean massive human suffering — well beyond what has already occurred within Iraq's borders," Crocker said.

The hearing fell on the anniversary of the Sept. 11 attacks.

"The fact of the matter is that American lives remain in jeopardy and, as I said, if every single jihadi in the world was killed tomorrow, we'd still have a major, major war on our hands," said Sen. Joseph Biden, D-Del., chairman of the Foreign Relations Committee, and a candidate for the Democratic presidential nomination.

Moderate lawmakers say there is plenty of room for compromise in the deeply divided Congress. Aides say bipartisan proposals are in the works and that Senate Majority Leader Harry Reid has reached out to several GOP senators to discuss potential common ground. However, a major hurdle remaining are politically influential organizations like MoveOn.org who say Democrats shouldn't water down the debate with more moderate legislation.