A U.S. Chinook helicopter (search) carrying troops to their R&R leaves was shot down as it headed for Baghdad airport on Sunday, killing 16 soldiers and wounding 20.
Witnesses said the attackers, hiding in a date palm grove, used missiles -- a sign of the increasing sophistication of Iraq's elusive anti-U.S. fighters.
Three other Americans were killed in separate attacks Sunday, including one 1st Armored Division (search) soldier in Baghdad and two U.S. civilians working for the U.S. Army Corps of Engineers in Fallujah (search). All three were victims of roadside bombs, the military said.
Sunday's death toll was the highest for American troops since March 23 -- the first week of the invasion that ousted Saddam Hussein -- and the attack represented a major escalation in the campaign to drive the U.S.-led coalition out of the country.
The giant helicopter was ferrying the soldiers on their way for leave outside Iraq when two missiles streaked into the sky and slammed into the rear of the aircraft, witnesses told The Associated Press. It crashed in flames in farmers' fields west of Baghdad.
"It's clearly a tragic day for America," Defense Secretary Donald H. Rumsfeld said in Washington. "In a long, hard war, we're going to have tragic days. But they're necessary. They're part of a war that's difficult and complicated."
Like past attacks on U.S. forces and a string of homicide 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.
President Bush, who was at his Texas ranch Sunday, refused to personally comment on the attacks. He spent the day out of public view -- a "down" day between campaign appearances Saturday and Monday.
L. Paul Bremer, the head of the occupation in Iraq, repeated demands that Syria and Iran prevent fighters from crossing their borders into Iraq.
"They could do a much better job of helping us seal that border and keeping terrorist out of Iraq," he said in a televised interview. The "enemies of freedom" in Iraq "are using more sophisticated techniques to attack our forces."
U.S. officials have been warning of the danger of shoulder-fired missiles, thousands of which are now scattered from Saddam's arsenals, and such missiles are believed to have downed two U.S. copters since May 1. Those two crashes -- of smaller helicopters -- wounded only one American.
The loaded-down Chinook was a dramatic new target. The insurgents have been steadily advancing in their weaponry, first using homemade roadside bombs, then rocket-fired grenades in ambushes on American patrols, and vehicles stuffed with explosives and detonated by homicide attackers.
In the fields south of Fallujah, some villagers proudly showed off blackened pieces of the Chinook's wreckage to arriving reporters.
Though a few villagers tried to help, many celebrated word of the helicopter downing, as well as a fresh attack on U.S. soldiers in Fallujah itself. Two American civilians working under contract for the U.S. Army Corps of Engineers were killed and one was injured in the explosion of a roadside bomb, the military said.
"This was a new lesson from the resistance, a lesson to the greedy aggressors," one Fallujah resident, who would not give his name, said of the helicopter downing. "They'll never be safe until they get out of our country," he said of the Americans.
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 on route for rest and recreation -- R&R.
The missiles semed to have been fired from a palm grove about 500 yards away, Thaer Ali, 21, said. At least one hit the Chinook, which came down in a field in the farming village of Hasai, a few miles south of Fallujah, witnesses said.
The missiles flashed toward the helicopter from the rear, as usual with heat-seeking ground-fired missiles. The most common model in the former Iraqi army inventory was the Russian-made SA-7, also known as Strelas.
Hours later, thick smoke rose from the blackened, smoldering hulk as U.S. soldiers swarmed over the crash site, evacuating the injured, retrieving evidence and cordoning off the area.
Yassin Mohamed said he heard the explosion and ran out of his house, a half-mile away.
"I saw the helicopter burning. I ran toward it because I wanted to help put out the fire, but couldn't get near because of American soldiers," he said.
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."
In Baghdad, Darley said the CH-47 helicopter belonged to the 12th Aviation Brigade, a Germany-based unit that supports the 82nd Airborne Division Task Force operating west of Baghdad.
The two Chinooks were carrying a total of more than 50 passengers to the U.S. base at Baghdad International Airport, from which they were to fly out on leave, U.S. officials said. Darley said some of the casualties were from medical units, but officials did not provide a breakdown of their units.
A spokesman at Fort Carson, Colo., said the Chinooks were carrying soldiers from Fort Carson; Fort Sill, Okla.; Fort Campbell, Ky.; and Fort Hood, Texas.
Lt. Col. Thomas Budzyna said some Fort Carson troops were among the injured but he did not know the units or bases of the other casualties.
"Many were looking forward to a break in the action," Budzyna said. "Unfortunately, they faced something else."
The Pentagon announced Friday it was expanding the rest and recreation leave program for troops in Iraq. As of Sunday, it said, the number of soldiers departing daily to the United States via a transit facility in neighboring Kuwait would be increased from 280 to 480.
Fallujah lies in the so-called "Sunni Triangle," a region north and west of Baghdad were most attacks on American forces have taken place. The downing and the soldier's death in Baghdad brought to at least 139 the number of American soldiers killed by hostile fire since President 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.
The death toll Sunday surpasses one of the deadliest single attacks during the Iraq war: the March 23 ambush of the 507th Maintenance Company, in which 11 soldiers were killed, nine were wounded and seven captured, including Pfc. Jessica Lynch. A total of 28 Americans around Iraq -- including the casualties from the ambush -- died on that day, the deadliest for U.S. troops during the Iraq war.
Meanwhile, in Abu Ghraib on Baghdad's western edge, U.S. troops clashed with townspeople Sunday. Local Iraqis said U.S. troops arrived in the morning and ordered people to disperse from the marketplace. Someone then tossed a grenade at the Americans, who opened fire, witnesses said.
The newest deaths capped a week of extraordinary carnage in and around Baghdad. On Oct. 26, a rocket slammed into a hotel housing hundreds of coalition staffers, killing one and injuring 15.
A day later, four coordinated homicide bombings in Baghdad killed three dozen people and wounded more than 200. Daily attacks against U.S. forces have increased in the last three weeks from an average of the mid-20s to 33.
The Associated Press contributed to this report.