WASHINGTON (AFP) - Stymied in their efforts to block

President George W. Bush's troop escalation in

Iraq, Democrats have scaled back challenges to his "surge," instead favoring legislation limiting the number of soldiers and length of their stay.

US Representative John Murtha (news, bio, voting record), one of the leading advocates in Congress for pulling US troops from Iraq quickly, said that Democrats have concluded that ending the war is not as easy as cutting off funding.

"We don't have the votes to do it," he told US television Sunday.

"And the public, they don't want that to happen. They want the troops to be entirely funded," Murtha said, speaking on NBC television's "Meet the Press" program.

Democrat Carl Levin (news, bio, voting record), who chairs the Senate Armed Services Committee, said that he too has abandoned efforts to end the US military mission in Iraq in favor of a plan that would simply reduce its scope.

"It will be a transition to a more limited mission of supporting the Baghdad army, training and logistics of that army. And we will, of course, have a limited presence for a targeted counter-terrorism mission, as well as trying to see if we can provide some support for the borders of Iraq," Levin told CBS television.

Levin said legislation to rein in the US military presence has a reasonable prospect of being approved by Congress where Democrats enjoy just a thin majority.

"If we can focus on ... keeping American troops out of the middle of a civil war ... with the understanding that there needs to be a limited mission that remains after that, I believe we can get almost all the Democratic votes, plus we can pick up some Republican votes," he told the CBS "Face the Nation" program.

Democrats took majorities in both houses of Congress in November 2006 elections, largely by voters disenchanted by the war in Iraq.

The House last month approved a non-binding resolution against Bush's prosecution of the war, but the bill failed to clear the Senate.