WASHINGTON - US lawmakers aimed for final approval of a a 789-billion-dollar stimulus package Thursday after a breakthrough deal that could give President Barack Obama a major victory by week's end.

"I want to thank the Democrats and Republicans in Congress who came together around a hard-fought compromise that will save or create more than 3.5 million jobs and get our economy back on track," Obama said Wednesday, adding he was grateful negotiations moved with the "urgency that this moment demands."

With the world's biggest economy facing what some have called its worst downward spiral since the Great Depression, quick but hard-fought negotiations among delegates from the Senate and House of Representatives yielded a deal Wednesday.

The agreement set up votes in the House and Senate, expected on Thursday and Friday, though the precise timing was not immediately clear.

Democratic House Speaker Nancy Pelosi, a key Obama ally, said she hoped to "take up the bill in the House and Senate in the next day or two" and that Obama would be able to sign it before his self-imposed February 16 deadline.

Senate Finance Committee chairman Max Baucus, an architect of the compromise, said he expected the House to vote on the titanic bill on Thursday, with the Senate following suit, perhaps on Friday.

"We just have to do what's right, rise to the occasion," he told reporters. "This could, along with other actions, I think... be the beginning of the end of this recession."

The final deal emerged after the House of Representatives approved 819 billion dollars last week and the Senate passed an 838-billion-dollar bill Tuesday, setting up negotiations to reconcile the rival versions.

Pelosi said she regretted cuts to certain items, including some money for school construction, but said the overall package includes "plenty there to create nearly four million jobs that the president has set as our goal."

Republicans charged that the final deal was the result of secret talks among House and Senate Democrats and three Senate Republicans, and pushed for a 48-hour delay during which the US public could consult the fine print online.

"What is the majority trying to hide?" asked the number two House Republican, Representative Eric Cantor, who warned against "action that we will later regret, action that possibly could do more harm than good to get us out of the economic crisis that we're in."

It was unknown whether the final vote would bring aboard more Republicans, none of whom backed the House version and just three of whom broke ranks to help push the package past the 60 votes needed to ensure Senate passage.

Supporters of the bill trumpeted what Democratic Senate Majority Leader Harry Reid called the "give and take" that produced the compromise.

Senator Susan Collins, one of the three swing-vote Republicans whose support was crucial to get Obama's mammoth plan through the Senate, said the new bill totaled 789 billion dollars.

"Today we have shown that, working together, we can address the enormous economic crisis facing our country," she said.

Collins said the total included about 150 billion dollars in infrastructure projects, adding that 35 percent of the total went to tax relief and billions more would help 49 states that face deep cuts in services to meet legal requirements that they produce balanced budgets.

"We do not have the luxury of time," said Democratic Senator Daniel Inouye, chairman of the Senate Appropriations Committee, warning: "We're a superpower. If we go down, there'll be chaos on this globe."

Obama pursued an aggressive political and public relations blitz to win support from wavering lawmakers, trekking to a construction site in northern Virginia to tout what he called his "urgent" and "essential" plan.

"We've got to get a final version to my desk so that I can sign it," said the president, hoping for a big legislative win after his young presidency suffered a series of early setbacks.