American troops launched a massive hunt for three missing comrades on Saturday amid fears they had been kidnapped by Iraqi insurgents during a pre-dawn attack that left five other soldiers dead. Soldiers and marines threw up roadblocks west of Baghdad as jets and helicopters were scrambled to join the search for the missing troopers.
"Make no mistake: we will never stop looking for our soldiers until their status is definitively determined, and we continue to pray for their safe return," said US spokesman Major General William Caldwell.
Earlier, at around 4:44 am (0044 GMT), a squad of seven American soldiers and an Iraqi army interpreter was attacked 20 kilometres (12 miles) west of Mahmudiyah, a restive town south of the capital, Caldwell said.
"As a result of this attack, five soldiers were killed in action and three are currently missing," he said, without indicating whether the dead were all US soldiers or whether the Iraqi interpreter was among those killed.
"At the time of the attack, a nearby unit heard explosions and attempted to establish communications, but without success," he added, in a statement. "Coalition forces arrived within an hour, secured the site, and immediately initiated a search. The names of the soldiers are being withheld pending final identification and notification of next of kin," he said.
Mahmudiyah is 30 kilometres (19 miles) south of Baghdad in an area of farmland and palm groves known as an insurgent stronghold. Since the US-led invasion of March 2003 the region has been nicknamed the "Triangle of Death."
Earlier, US marines patrolling west of Baghdad near the Sunni city of Fallujah told an AFP reporter travelling with them that they had been told the missing soldiers were thought to have been captured.
"We got word about 0900 (0400 GMT) that three soldiers were missing. Last we heard was that they were headed in this direction, presumed captured," said Gunnery Sergeant James Curtis of the US Marines 2nd Battalion 6th Regiment.
His patrol set up a checkpoint on a road on the eastern edge of Fallujah in a bid to intercept the abductors if they tried to bring their captives there from the area west of Baghdad.
Some trucks and cars arriving at the roadblock were marked as having already been searched, showing that other military checkpoints had been set up on the road from Fallujah to both Mahmudiyah and the capital. "Checkpoints have been established throughout the area in a concerted effort to focus the search and prevent potential movement of missing soldiers out of the area," Caldwell's statement said.
"Coalition forces have engaged with local leaders to enlist their support in providing any information they can, and these engagements continue." Iraqi security forces said they had shot dead a "terrorist" in Mahmudiyah on Saturday, but it was not clear whether this was linked to the earlier attack.
While US forces in Baghdad and west and central Iraq come under attack daily from roadside bombs, snipers and guerrilla fighters, it is rare for insurgents to succeed in capturing American personnel.
Nevertheless, al Qaeda in Iraq - a Sunni group that has posted Internet videos of slain American and Iraqi hostages - has made it clear that capturing US service members is a priority. Shiite militants have also captured Americans in the past.
On January 20, gunmen disguised in US army uniforms breezed past security checks and attacked a provincial security building in central Iraq's Karbala province during a visit by American troops to their Iraqi counterparts.
One US soldier was killed and four more were captured. Their bodies were later found with the attackers' abandoned SUV vehicles, along with disguises and US-style weapons and radios.
The US commander in Iraq, General David Petraeus, later said the cell suspected of having carried out the murders had received support and funding from Iranian agents, but did not link Tehran directly to the attack. In June 2006 an al Qaeda-linked website said the group's alleged leader - known under the nom de guerre "Sheikh Abu Hamza al-Muhajer" - had ordered the killing of two kidnapped American soldiers.