WASHINGTON — The White House said yesterday that it would send lawmakers a revised proposal for dealing with terrorism suspects as indications grew that President Bush’s plan was meeting increased resistance among Republicans in both chambers of Congress.

The White House’s deputy press secretary, Dana Perino, said the administration was sending the new language in hopes of reaching an agreement. A revolt by GOP senators, who have written their own proposal giving suspected terrorist detainees more rights than the administration wants, has embarrassed the White House at a time when Republicans want to use their security policies as a main platform in November’s congressional elections.

“Our commitment to finding a resolution is strong,” Ms. Perino said.

A week after a Republican-led Senate committee defied Mr. Bush and approved legislation on suspected terrorist detainees that the president vowed to block, three more GOP senators said they now opposed the administration’s version, joining the four Republicans who had already come out against it.

If all 44 Democrats plus the chamber’s Democratic-leaning independent also vote for the alternative by Senator Warner, a Republican of Virginia, as expected, that would give it a majority in the 100-member Senate.

In a further hint of problems for the administration, House officials said their chamber was postponing a vote planned for tomorrow on a bill mirroring Mr. Bush’s proposal.

Republican officials, speaking on condition of anonymity, said they have encountered resistance and were no longer certain they had enough votes to push the measure to passage through the GOP-run House.

A spokesman for House Majority Leader John Boehner, a Republican of Ohio, Kevin Madden, said the vote would be rescheduled to next week and blamed the delay on a request by the House Judiciary Committee to study the bill.

An administration official, who declined to be identified because of the sensitivity surrounding the negotiations, said the new language only addresses a dispute over the nation’s obligations under the Geneva Conventions, which set the standard for treatment of prisoners taken during hostilities.

No other details of the new administration plan were initially available.

“This legislation, once finished, will provide not only a way to bring the mastermind of 9/11 to justice, but also provide clarity to our men and women in the intelligence community who are interrogating these high-value detainees who helped provide information that allowed us to disrupt and prevent additional terrorist plots against America,” the White House’s Ms. Perino said.

The president’s measure would go further than Mr. Warner’s bill, allowing classified evidence to be withheld from defendants in terror suspect’s trials and allowing coerced testimony. Mr. Bush also favors a narrower interpretation of the Geneva Conventions that would make it harder to prosecute American interrogators for using harsh techniques.

Neither side is saying how an agreement can be achieved on whether to allow the CIA to use highly contentious methods such as disorientation, forced nakedness, and waterboarding, in which a subject is made to think he or she is drowning. Without confirming any specific techniques used by the CIA, the Bush administration says the agency’s program has foiled terror plots. Opponents say the techniques verge on or are equivalent to torture.

Last week, Mr. Warner, normally a supporter of Mr. Bush, pushed his measure through his Senate Armed Services Committee by a 15–9 vote. The White House argued that the Senate proposal would end the CIA program to interrogate suspected terrorists.

Whether Mr. Bush would have enough votes to win on the Senate floor seemed in question. Yesterday, Mr. Warner appeared to have the majority of support in the Senate, with at least 52 votes in his favor if Democrats backed him, as expected.

GOP Senators Hagel of Nebraska, Chafee of Rhode Island, and Snowe of Maine said they favor Mr. Warner’s bill, joining Mr. Warner and three others who voted for it during the committee meeting last week.

Neither side has been able to muster definitively the 60 votes necessary to prevent a Senate filibuster of their proposal. This uncertainty — along with hope that the White House and Mr. Warner would reach an agreement to stave off a Republican showdown on the Senate floor — has kept the bill from being voted on.

The Senate’s majority leader, Bill Frist, a Republican of Tennessee, who supports the president’s bill, has said he wants to pass it before lawmakers recess at the end of the month. Doing so would allow the president to proceed with prosecutions of 14 “high-value” suspected terrorists before the midterm elections.

The president’s plan has encountered resistance in the House as well, with Rep. Steve Buyer, a Republican of Indiana, urging Mr. Bush to heed the military’s top uniformed lawyers, who have previously opposed some provisions of the president’s plan.

An agreement would keep Republicans from having to choose between backing Mr. Bush, as they have done in the past on anti-terror issues, and three Republicans known as leaders on national security issues: a former Navy secretary, Mr. Warner; a former prisoner of war who last year pushed through legislation banning mistreatment of detainees and Republican of Arizona, Senator McCain, and a reserve judge for the Air Force Court of Criminal Appeals and Republican of South Carolina Senator Graham.