BAGHDAD - Mortar rounds hammered the U.S.-controlled Green Zone for a second day yesterday, killing at least two people, wounding about 10 more and raising new fears for the safety of workers at the nerve center of the American mission in Iraq.

About a dozen shells crashed into the 3.5-square-mile area of central Baghdad about 4 p.m., sending terrified pedestrians racing for the safety of concrete bunkers.

Motorists abandoned their cars and sprinted for cover. Sirens wailed and loudspeakers warned people to seek safety.

No American casualties were reported, and the two dead as well as most of the wounded were Iraqis, U.S. Embassy spokesman Lou Fintor said.

An Iraqi security officer said one of the dead was a driver for the staff of Prime Minister Nouri al-Maliki, whose office is in the Green Zone. The officer spoke on condition of anonymity because he was not supposed to release the information.

Meanwhile, in Washington, anti-war Democrats in the Senate failed in an attempt to cut off funds for the Iraq war, a lopsided bipartisan vote that masked growing impatience within both political parties over President Bush's handling of the four-year conflict.

The 67-29 vote against the Democrats' measure left it far short of the 60 needed to advance. But more than half the Senate's Democrats supported the move, a marked change from last summer when only a dozen backed a troop withdrawal deadline.

"It was considered absolute heresy four months ago" to stop the war, said Sen. Russell Feingold of Wisconsin, author of the measure to cut off funds for most military operations after March 31, 2008. Nowhere was the shift more evident than among the Senate's Democratic presidential contenders.

For the first time, Sens. Hillary Rodham Clinton, of New York, Barack Obama, of Illinois, and Joe Biden, of Delaware, joined Sen. Chris Dodd in supporting the idea of setting a date to end U.S. participation in the war.

Among them, only Clinton stressed the procedural nature of her vote, declining to say she would ultimately vote to cut off funding if given a chance. *