Sunday's missile attack, which also wounded 20 troops, closed out a week that began with a similarly grim new record. On Oct. 27, three dozen people died in a wave of suicide bombings in Baghdad, the bloodiest day there since President Bush declared major combat over May 1.
Mr. Bush, spending a long weekend at his Texas ranch, said nothing in person about the helicopter shoot-down Sunday, a day in which three other Americans, including two civilian contractors, also were killed in Iraq.
But White House spokesman Trent Duffy, in a statement read to reporters, said: "The terrorists seek to kill coalition forces and innocent Iraqis because they want us to run, but our will and resolve are unshakable."
The attack was the single deadliest event of the war for U.S. troops, which began in March. The U.S. deaths Sunday brought to at least 139 the number of American soldiers killed by hostile fire since Mr. Bush declared an end to combat on May 1.
Around 377 U.S. service members have died since the beginning of military operations in Iraq. Daily attacks against U.S. forces have increased in the last three weeks from an average of the mid-20s to 33.
Witnesses said the attackers used missiles to down the Chinook — a sign of the increasing sophistication of Iraq's elusive anti-U.S. fighters. As a result, CBS News Reporter Charles D'Agata reports, U.S. commanders have suspended daylight flights by Chinooks.
In other developments:
The White House statement sought to remind Americans that Mr. Bush sees military action in Iraq as tied to the Sept. 11 terror attacks — and as part of a larger battle to head off future attacks.
"Sept. 11 taught us that we must confront terrorists and outlaw regimes with weapons of mass murder before it is too late," Duffy said. "The only way to win the war on terror is to take the fight to the enemy."
Sen. Joseph Biden, the ranking Democrat on the Senate Foreign Relations Committee, told the CBS News Early Show that the United States must finish the job it started in Iraq.
However, Biden criticized the Bush administration's war effort for lacking a "sense of urgency" in securing the peace and said more troops are needed for the job.
The United States, he said, needs to "bring in NATO, bring in other folks and give up some authority. We act like Iraq is some kind of prize that we won."
Speaking Sunday, Defense Secretary Donald H. Rumsfeld said Americans should view the deadly downing of the Army helicopter as the tragic but inevitable cost of waging a long war.
"In a long, hard war, we're going to have tragic days, as this is," he said. "But they're necessary. They're part of a war that's difficult and complicated."
But Democratic presidential hopefuls seized on the downing of the helicopter to press the administration to justify the mounting American death toll and to explain its strategy for getting out of Iraq.
"We were misled into this conflict without a real strategy for success," former NATO commander Wesley Clark told The Associated Press.
Two other candidates, Rep. Dick Gephardt and Sen. John Edwards, said the United States needs more international help to make Iraq safe.
"We cannot solve this problem alone," Gephardt said on CBS television. He urged Mr. Bush to sit down with foreign leaders, "treat them with respect and…get the help that we should get from our friends."
Dennis Kucinich, the only Democratic candidate who voted against the congressional resolution authorizing the war in Iraq, said in a statement: "This disastrous mission must be ended before any more lives are lost…It is time to bring our troops home."
The downed copter was one of two Chinooks flying out in formation from an air base in Habbaniyah, about 10 miles from the crash site, carrying troops to Baghdad enroute to long-awaited two week-long leaves from combat duty.
The U.S. military would not confirm that the aircraft was struck by a missile, but a spokesman, Col. William Darley, said witnesses reported seeing "missile trails."
The helicopter crashed in flames in farmers' fields west of Baghdad.
Some villagers proudly showed off blackened pieces of the Chinook's wreckage to arriving reporters. Though a few villagers tried to help, many celebrated.
Like past attacks on U.S. forces and a string of suicide bombings that killed dozens in Baghdad the past week, U.S. coalition officials blamed either Saddam loyalists or foreign fighters for the strike outside Fallujah, a center of Sunni Muslim resistance to the U.S. occupation.
By targeting U.S. aircraft, the insurgents in Iraq stand a greater chance of killing sizable numbers of Americans in a single strike.
U.S. officials have been warning of the danger of shoulder-fired missiles, thousands of which are now scattered from Saddam's arsenals.
Officials were unsure if the strike against the helicopter was part of a "day of jihad" threatened last week in leaflets seen in Baghdad, which promised new attacks against U.S. forces involving "modern and advanced weapons."