The Bush administration has threatened to veto a major spending bill unless Congress reverses proposed cuts in the president's signature space initiatives to return to the moon.

The written warning from White House budget director Joshua B. Bolten marks an unusual departure from administration criticism of rampant congressional spending.

It came late Thursday, just hours after House Majority Leader Tom DeLay (R-Tex.), who disapproves of the proposed cuts, raised his concerns with President Bush and White House Chief of Staff Andrew H. Card Jr. The bill in the White House sights is a $92 billion measure that also includes a $1.2 billion increase in veterans programs in 2005.

Bush made headlines in January when he outlined his "Vision for Space Exploration." He promised to "extend a human presence across our solar system" with a return to the moon by 2020 and eventual human space travel to Mars.

DeLay, whose newly drawn district includes the Johnson Space Center in Houston, has been one of the plan's most vocal supporters. In a June 3 speech on the House floor, he acknowledged that funds were tight, but added that "for four decades, America's mission in space has been one of the surest economic investments the federal government has made. . . . Despite the costs, risks and hardship, we can get there from here."

Citing budgetary constraints, the House Appropriations Committee on Thursday slashed the administration's request for the National Aeronautics and Space Administration by $1.1 billion -- eliminating $438 million NASA had sought to begin work on a new "crew exploration vehicle" to replace the space shuttle, cutting its request for medical and biological research in space by $103 million, and reducing funds sought for lunar exploration by $70 million.

The administration supports an increase of only 1 percent for programs unrelated to defense and counterterrorism. The limit has forced Congress to make tough choices and has led to cuts or outright elimination of a number of presidential initiatives.

Earlier this year, for example, a House spending bill deleted funds for new civics education and art exchange programs that are championed personally by the president and first lady.

Though the White House has expressed disappointment in such actions, there has been no veto threat.

But in this case, Bolton sent a letter to House Appropriations Committee Chairman C.W. Bill Young (R-Fla.) and others, stating that a veto would be recommended unless presidential initiatives receive "adequate funding levels."

Bolton also complained of cuts in the president's requests for the Prisoner Re-entry Initiative -- which would use faith-based groups to assist released inmates -- and the AmeriCorps national service program, a favorite of Laura Bush.

Of most concern were the proposed funding levels for NASA, which "would drastically delay plans for Fiscal Year 2005 critical technology design efforts that are needed to begin to implement the President's Vision."

There was no indication, however, that House members charged with drawing up the NASA budget planned to retreat from their decision.

Rep. James T. Walsh (R-N.Y.), who chairs the Appropriations subcommittee responsible for NASA, said in a statement that: "Our committee was given an extremely tight allocation this year, and it met its number one priority to increase veterans healthcare funding as authorized in the Budget Resolution passed by the House. Our goal was to create a fair bill, and I believe that we did."

Other members of Congress have suggested that flagging interest in the space initiatives by the Bush administration itself made the programs a logical target for cuts, given overall budget constraints.

"The president marketed this as a bold proposal, but has only espoused it one time," said Rep. Alan P. Mollohan (D-W.Va.), ranking minority member of the House Appropriations subcommittee that oversees NASA. "His silence since the initial proposal is deafening."