WASHINGTON (AP) – Republican lawmakers pressed the White House on Friday for deeper spending cuts than President Bush will propose in his new budget on Monday.

Separately, officials said the budget will seek a boost for fighting AIDS abroad and a modest increase for education.

White House budget chief Joshua Bolten briefed GOP senators and representatives gathered in Philadelphia on Bush’s fiscal plan, telling them it would project a $521 billion deficit for this year, said administration and congressional officials speaking on condition of anonymity. That would far exceed last year’s $375 billion shortfall, the highest ever in dollar terms.

In more than two hours of questions and comments, many lawmakers said they wanted sharper spending reductions than Bush will propose. While seeking steep increases for defense and domestic security, the president will propose holding other programs to 0.5 percent growth, well below the inflation rate, administration and congressional officials said.

“Grave concern was expressed about the overall level of spending,” conservative Rep. John Shadegg, R-Ariz., said of legislators’ comments to Bolten. “And he was very forthcoming about saying the administration could work with members’ concerns.”

Though some moderate Republicans voiced support for deeper spending cuts, others questioned whether there would be enough support – especially in an election year – for holding many popular programs to less than the inflation rate.

The back-and-forth underlined the difficulties Bush will have in pushing his budget proposals through the GOP-run but divided Congress. Many moderates will be loath to vote for deep reductions, while Democrats are sure to use proposed cuts as fodder in election campaigns.

Meanwhile, fresh details emerged about proposals in the $2.3 trillion spending plan Bush reveals Monday, including:

• $2.7 billion for efforts to battle AIDS and other diseases in poor African and Caribbean countries. Congress provided $2.4 billion this year, $400 million more than Bush requested.

• $2.5 billion for the Millennium Challenge Account, which Bush and lawmakers created last year for countries adopting democratic reforms. Bush won $1 billion this year, $300 million less than he wanted.

• An overall 3 percent boost for education, which got $58.6 billion for this year. Bush has said there will be $1 billion increases within that total for both special education and low-income school districts. Rural education spending is among several school programs he will propose cutting.

The details were provided by congressional and administration officials.

Also emerging was more information about the $401.7 billion budget Bush will request for the Pentagon, which accidentally posted parts of the proposal on its Web site. That would be a 7 percent increase over this year.

The figures showed that the request for procurement will be $74.9 billion, $6.2 billion less than this year. Research and development would grow to $68.9 billion from $64.7 billion, including $2.7 billion – a near doubling – to modernize the Army’s armored weapons.

Republicans met in Philadelphia as Bush and Bolten continued fending off conservatives angry over new administration estimates that the just-enacted Medicare and prescription drug bill would cost $534 billion in the decade ending 2013. That is a third higher than the $395 billion Congressional Budget Office estimate that administration officials and congressional GOP leaders cited as they pushed the legislation through Congress in November.

At the White House, Bush defended the Medicare package as “a good reform, it fulfills a long-standing promise to our seniors.”

He said the higher cost estimates would not prevent him from meeting his goal of halving the deficit by 2009, saying lawmakers would have to help him.

“Congress is now going to have to work with us, to make sure that we set priorities and are fiscally wise with the taxpayers’ money,” Bush told reporters. “I’m confident they can do that if they’re willing to make tough choices.”