WASHINGTON -- As House Democrats return to the nation's capital today, Pennsylvania's Rep. John Murtha finds himself in the middle of a political tempest that is threatening to splinter party unity on the Iraq war.

Mr. Murtha, a Johnstown Democrat who heads the powerful subcommittee on defense appropriations, has said he plans to add stringent restrictions to the Bush administration's request for nearly $100 billion in extra money for fighting in Iraq and Afghanistan, including firm training and equipment readiness benchmarks for units heading overseas and mandatory rest periods of at least one year between deployments.

Republicans started attacking Mr. Murtha's proposals before last week's congressional recess, calling it a "slow bleed" approach to cutting off funds for the war and limiting the flexibility of military commanders on the battlefield.

Those attacks have put Democrats on defense and are exposing fissures even within the party's 11-member Pennsylvania delegation. Many, including House Speaker Nancy Pelosi, D-Calif., say they are waiting to see Mr. Murtha's proposals in writing before signing on.

"I will not support anything that reduces funding for the troops or can be perceived as reducing funding for the troops," said Rep. Jason Altmire, D-McCandless. "It's very clear-cut for me."

Rep. Joseph Sestak, a freshman Democrat from Delaware County and a retired three-star Navy admiral, told the New York Times last week that he had the "greatest respect" for Mr. Murtha but was "wary."

"Congress is a blunt instrument," he said. "There may be unknown ramifications, unintended unknown ramifications, when you get on the operational level."

Mr. Murtha, 74, has become one of the nation's most visible and vocal critics of the war in Iraq, and his party has held up the decorated Vietnam veteran as a standard bearer on the issue.

In response, Republicans have been harsh critics of Mr. Murtha, and they sharpened their attacks on the former Marine this month when he granted an interview to MoveCongress.org, an anti-war group.

The interview was posted on the group's Web site one day before Congress voted on a resolution criticizing President Bush's plan to send more than 20,000 extra troops to Iraq, with Mr. Murtha saying the nonbinding measure was just a prelude to a "real vote" that would block the troop surge.

"They know they can't sustain the surge if [my proposal] passes the House and the Senate," he said. "And the president could veto it. But then he wouldn't have any money."

The next day, several Republican leaders slammed Mr. Murtha during a debate on the House floor. The vote on the anti-surge resolution largely fell along partisan lines, with 17 Republicans, including Rep. Phil English of Erie, joining 229 Democrats to approve it.

Brian Kennedy, a spokesman for House Republican Leader John Boehner of Ohio, said the MoveCongress.org interview helped keep more Republicans from breaking ranks.

"I think the Murtha plan is best characterized as a slow-bleed approach to retreating from the war," he said. "When it comes to funding the troops who are in harm's way, Republicans will continue to stand united."

Democrats counter that Mr. Murtha is trying to ensure that soldiers get needed rest, training and equipment after repeated deployments, although even Mrs. Pelosi, a longtime ally of the Pennsylvania lawmaker, yesterday was unwilling to voice full support for his proposal.

"We haven't really seen a final version of that. That will have to go through the committee, the Appropriations Committee. But I don't see much opposition to the idea that our troops should be trained if they go into harm's way," she said. "Congress will fund our troops. We've said that over and over again."

Mr. Murtha, who was unavailable for an interview yesterday, will meet with Democratic leaders tomorrow to detail his ideas, according to a spokesperson, Megan Grote. He also is planning to hold a press conference later in the week.

Even if Mr. Murtha can win support, his approach could face a rocky reception in the Senate, where leading Democrats are focusing on trying to rescind parts of the 2002 war authorization that allowed President Bush to launch the Iraq war. Republicans have threatened to block such changes.

Sen. Arlen Specter, R-Pa., last week said he still has questions about the extent of congressional power over the war. He is calling for the Senate Judiciary Committee, where he is the ranking Republican, to hold hearings on the issue.

Rep. Mike Doyle, D-Forest Hills, a strong Murtha ally, said Congress needs to take binding action on the war, and he accused Republicans of trying to avoid a real debate.

"They'll do anything to divert the public's attention," he said. "I think the American people are way ahead of us, and Murtha said the same thing."