The Pew Research Center poll released Monday found that 46 percent of Americans favor bringing the troops home as soon as possible, up from 36 percent last October. The nonpartisan survey of 1,464 Americans, conducted June 8-12, also found that less than half of the respondents - 47 percent - now believe the U.S. will accomplish its goals in Iraq.

The findings come on the heels of a Gallup Poll in which nearly six in 10 Americans say they favor either a partial (31 percent) or total (28 percent) pullout of U.S. troops.

After Iraq's independent election earlier this year, "there was a burst of optimism," said Pew associate director Carroll Doherty. For Americans, he said, "it had the effect of, if not raising optimism, staving off some pessimism. But since then, most of the news people see has been bad 0 suicide bombings, U.S. troops being killed. It's pretty unrelenting.

"Troops are dying, and people don't see an end game, a way out," he said. "It's this idea that we're in for the long haul and things, at least in perception, aren't getting better."

Just prior to President Bush's re-election last fall, Americans were strongly in favor, by a 57-to-36 margin, of keeping U.S. troops in Iraq until the situation stabilized. But since then that gap has steadily shrunk, so that now 50 percent want the troops to remain and 46 percent want them brought home.

The findings come as Democrats and even an occasional Republican are stepping up their criticisms of Bush's strategy in Iraq, where more than 1,700 U.S. troops have died, and of the operation of an embattled military prison at Guantanamo Bay, Cuba.

Rep. Walter Jones, R-N.C., who advocated calling French fries "freedom fries" after France opposed the U.S. invasion, said on ABC's "This Week" that he and some of his colleagues would offer legislation calling for a timetable for withdrawing troops.

And the top Democrat on the House Judiciary Committee, Rep. John Conyers Jr. of Michigan, plans to hold an unofficial hearing this week on whether the Bush administration had decided as early as the summer of 2002 to invade Iraq, as Conyers says a British government memo suggests.

The Bush administration has repeatedly rejected the idea of setting timetables for troop withdrawal from Iraq, saying that would only give leverage to terrorists and insurgents.

"The president believes it is vital that we complete our mission, and that means training Iraqi security forces," spokesman Scott McClellan said Monday. "Then our troops can return home with the honor they have deserved."

McClellan also defended the U.S. operation at Guantanamo.

"We remain a nation at war," he said. "The individuals who are at Guantanamo Bay are dangerous terrorists who seek to do harm to the American people."

At the same time, he said Bush believes "we should always be looking at our options" when it comes to dealing with detainees.

Pew's survey found Americans are not as concerned about the situation at Guantanamo, with 54 percent saying reports of mistreatment of suspected terrorists represent isolated incidents and 34 percent saying they are part of a more widespread pattern of abuse.

"In Washington, I don't think Bush is seeing anything close to a real problem within his party," Doherty said. "I do think you're seeing individual voices, but not the rank and file. I do think individual members of Congress are hearing about this at home, and if they are criticizing the president a little bit more on Iraq, it probably reflects what they're hearing from their constituents."