On Saturday, seven Spanish intelligence agents and two Japanese diplomats died in separate attacks near Baghdad.
The latest deaths bring to 104 the number coalition troops who have died in Iraq in November, with 79 American soldiers slain along with 25 other allied troops. In terms of coalition losses, it has been the bloodiest month of the war that began March 20.
A military statement said the U.S. troops were killed when a task force from the 3rd Armored Cavalry Regiment was hit Saturday by rocket-propelled grenades and automatic fire east of the border town of Husaybah, 180 miles northwest of Baghdad.
Near Tikrit, gunmen shot and killed two South Korean workers and wounded two others, Iraq, South Korea's Yonhap news agency reported.
The U.S. military in Baghdad said a Colombian civilian working as a contractor for the military was killed Saturday in an ambush on a convoy. It was not immediately clear if he died in the same attack as the South Koreans.
In other developments:
On Sunday, the U.S. military for the first time acknowledged that the single deadliest incident of the war — the collision of two Black Hawk helicopters in Mosul on Nov. 15 — may have been caused by enemy action. Until now, the military had not speculated publicly on the cause of the collision in which 17 soldiers died.
"It appears to be that one helicopter was hit by a (rocket-propelled grenade)," said Col. Joe. Anderson, commander of the 2nd Brigade of the 101st Airborne Division.
"This is all still under investigation but it appears that there was some form of ground fire, probably an RPG that hit one which caused one to collide," he said.
The Spanish military intelligence officers were ambushed on Saturday in Mahmudiyah, 18 miles south of Baghdad. Seven Spaniards were killed and one escaped the assault.
In Baghdad, Brig. Gen. Mark Kimmitt said the attack showed that the enemy was switching the focus of attacks from coalition troops to what he described as "soft targets."
"This is a clever adaptive enemy (but) he is also facing a clever and adaptive enemy," Kimmitt said.
On Sunday, witnesses at the scene of the ambush about 50 kilometers (30 miles) south of Baghdad, said the Spaniards had been traveling in a pair of sport utility vehicles when men in a car behind them opened fire. One of the SUVs careened off the road into a ditch.
The occupants fled the car and were shot at the roadside, perhaps by a second group of attackers involved in the ambush. On Sunday, the charred remains of the car could be seen in a watery ditch at the side of the road, with a group of villagers scavenging its parts.
Witnesses said the four men in the second car were also killed at the side of the road nearby, apparently by a grenade. Blood could be seen on bushes nearby, and a broken pair of glasses lay on the road.
Spanish defense minister Federico Trillo arrived in Kuwait Sunday to repatriate the bodies, which were flown to Kuwait's International Airport aboard a C-130 Hercules transport, officials in Madrid just said.
The two Japanese diplomats were killed by unidentified gunmen Saturday as they stopped to buy food and drinks at a stand outside the village of Mukayshifa on the road between Baghdad and Tikrit, Lt. Col. William MacDonald said Sunday.
The diplomats, on their way to attend a reconstruction conference, were not traveling with a military escort, MacDonald said. Their Iraqi driver was also reported killed in the incident.
The attacks on U.S. allies appear to be part of an effort to undercut the coalition. Insurgents also have targeted Iraqis seen as collaborating with the occupation authorities, such as police and local officials.
In Tokyo, Japanese Foreign Minister Yoriko Kawaguchi said there would be no change to Japan's plans to dispatch troops to support the U.S.-led reconstruction of Iraq. The deaths were the first of Japanese in Iraq since the U.S.-led invasion.
Spokesmen for Spanish Prime Minister Jose Maria Aznar also affirmed that the attack wouldn't cause Spain to end its presence in Iraq.
Spain was one of the firmest supporters of the U.S.-led invasion to oust Saddam Hussein and sent 1,300 soldiers to help maintain order. A Spanish diplomat attached to Spain's intelligence agency was assassinated near his residence in Baghdad on Oct. 9, and a Spanish navy captain was killed in the truck bombing of the United Nations headquarters in Baghdad on Aug. 19.