President Bush's latest bid for a Middle East peace deal is running into unexpected resistance from key allies in Congress. Republicans and Democrats are pressing the White House to adopt a more staunchly pro-Israel stance, even if it feeds the perception the United States is too closely aligned with Prime Minister Ariel Sharon's government.

In a rare public split with the Bush administration over foreign policy, and at a critical moment in international relations, GOP congressional leaders are calling on the president and Secretary of State Colin L. Powell to temper their support for a long-awaited Middle East peace plan designed to implement Bush's call in June for the creation of a Palestinian state within three years. Israel has objected to certain parts of the plan, known as the "road map," which was drafted last year by the so-called quartet -- the United States, the European Union, Russia and the United Nations.

The plan envisions a three-stage process that would create Palestinian institutions, establish provisional borders for a state by the end of this year and reach a final agreement with defined borders in 2005. Completed in December, the road map's release was delayed at Sharon's request until after the January Israeli elections, and again until the Palestinian legislature confirmed a new prime minister. That confirmation is to occur by the end of this month, and the imminent release of the plan has brought stepped-up concern.

Republicans and Democrats say they worry that the administration is undercutting Israel by embracing the plan. "There are many members of Congress concerned about this road map," House Majority Leader Tom DeLay (R-Tex.) said in an interview yesterday.

Sharon's government, and many in Congress, object to the non-negotiable nature of the document and to its demand that Israel and the Palestinian take parallel steps to move toward peace. Israel's position is that the Palestinians must prove they have stopped all terrorism, and activities that Israel believes promote terrorist activities, before it is required to take any steps, including the withdrawal of troops and stopping the expansion of settlements in occupied Palestinian territory.

In speeches this week and a letter scheduled for delivery later this month, GOP and Democratic congressional leaders -- who are competing for Jewish voters and donors -- make clear they will oppose any peace deal that does not first require the Palestinians to change their government and end all terrorist activities before imposing significant requirements on Israel. Several key Republicans said Bush has privately assured them that he agrees with them. But they expressed concern that Powell and British Prime Minister Tony Blair might manage to soften his resolve.

"There is a fairly healthy debate, even in this administration, about how you get to a place of true peace," said House Majority Whip Roy Blunt (R-Mo.).

Although Bush pledged his "personal commitment" to the road map in a March 14 speech, he said he welcomed additional "contributions" to the plan. That raised concern among other quartet members that he was open to Israeli suggestions for changing the document. Congressional opponents of the plan saw this as confirmation that Bush's commitment was not total.

DeLay rewrote a speech he delivered Wednesday night to warn against treating the Palestinian Authority as a trustworthy negotiating partner, an aide said. "Negotiating with these men . . . is folly, and any agreement arrived at through such empty negotiations would amount to a covenant with death," DeLay told a fervently pro-Israel crowd at a conference of Jews and Christians in Washington. "Experience and common sense lead to one conclusion about America's proper role in the Middle East: We are absolutely right to stand with Israel, and our opponents are absolutely wrong." DeLay said it was "absurd" for the State Department this week to report that Israel has a poor human rights record. The newly released annual document criticized Israel and the Palestinians for abuses over the past year.

Several Republican and Democratic leaders plan to send Bush a letter this month signed by dozens of members, imploring him to adopt a position more clearly backing the Sharon government. "There are concerns about Bush's" recent comments, said House Minority Whip Steny H. Hoyer (D-Md.), an outspoken supporter of the war in Iraq and co-author of the letter. "We think this is not the direction he ought to go."

Blunt, a key Bush ally, is the highest-ranking Republican to sign the letter, which was first reported by CQ Today, a Capitol Hill publication. "This would not be the first time some people would question the president's commitment to a position only to have some immediate proof he's committed to [Israel]," Blunt said in an interview.

Criticism from Congress and pro-Israel activists could complicate Bush's on-again, off-again campaign to bring peace to the Middle East. Lawmakers and pro-Israel activists said Bush would have trouble selling the peace process to U.S. voters if much of Congress opposes it.

The criticism also might undermine Bush's campaign to win greater support from the United States' comparatively wealthy and politically active Jewish community, lawmakers and GOP fundraisers say. Indeed, some Republicans attributed the fervently pro-Israel language by DeLay and other party leaders to their months-long campaign to attract Jewish donors, who traditionally have given the bulk of their money to Democrats.

Israel in recent years has made great strides in winning the support of conservative Republicans, especially evangelical Christians such as DeLay who view Israel as the biblical promised land.

Bush, an unwavering supporter of Sharon, has been lobbied heavily by Blair and Powell to follow through with the road map. Along with a number of U.S.-friendly Arab governments and most of Europe, Blair believes that movement in the peace process is a crucial follow-up to the war in Iraq. Blair's unwavering support for Bush's war policy against Iraqi President Saddam Hussein is based in part on the president's commitment to the plan.

But the approach of its release, and speeches this week in which Powell and national security adviser Condoleezza Rice reiterated Bush's March 14 pledge, have drawn the attention of congressional opponents. In remarks before the American Israel Public Affairs Committee, an influential pro-Israel group, both reaffirmed support for an end to "settlement activity" in the occupied territories and the White House's commitment to the road map. Rice conceded the plan is "controversial," but said it comports with the vision Bush laid out last summer.

House Minority Leader Nancy Pelosi (D-Calif.) told the same AIPAC audience that she was "seriously concerned about the timing, tone and effect of the president's statement of March 14. Let there be no weakening in our resolve, no softening in our stance, no lowering of the threshold for the cessation of violence."

House Speaker J. Dennis Hastert (R-Ill.) told the audience, "we need to be wary" of dealing with Russia, the European Union and United Nations on a peace deal. "They have never been strong supporters of Israel."

In separate comments, Rep. Eric I. Cantor (R-Va.), the House's only Jewish Republican, said that "with recent elevation of the road map and the mention of the road map, it has gotten the attention of all of us."

A senior White House official acknowledged that "there is nervousness in some parts of the Jewish community," but said "the president thinks it's important to proceed."

House International Relations Committee Chairman Henry J. Hyde (R-Ill.), Blunt and other lawmakers plan to call on Bush to demand new Palestinian leadership "with real authority," a cessation of terrorism and the creation of a Palestinian security apparatus before a Middle East peace process proceeds. These principles "form the only sensible basis for moving ahead with peace," they plan to say in the letter being readied for later this month.

Staff writer Karen DeYoung contributed to this report.

House Majority Leader Tom DeLay (R-Tex.) cited concern that the United States is undercutting Israel.