Two female suicide bombers carried out an attack which killed three coalition soldiers at a checkpoint north-west of Baghdad on Thursday, Iraq says.
Two women brandished rifles in videotaped messages
A pregnant woman who ran from the car just before the explosion died in the blast as did the driver of the vehicle, who Iraq's official news agency said was also a woman.
The Arabic television station al-Jazeera broadcast separate videotapes of two Iraqi women, one saying she was seeking "martyrdom" and the other threatening a jihad or holy war against American, British and Israeli "infidels".
US Central Command in Qatar said the incident occurred on
Thursday evening 18 kilometres from the Haditha Dam and about 130 km (80 miles) from the Iraq-Syria border.
"A pregnant female stepped out of the vehicle and began
screaming in fear," a statement said.
"At this point the civilian vehicle exploded, killing three coalition force members who were approaching the vehicle and wounding two others."
The apparent suicide attack occurred in an area where special forces are present but where US-led forces are thin on the ground.
US Marine Captain Stewart Upton told the Reuters news agency: "We are treating it as another desperate act of a dying
regime that knows they're in trouble."
The BBC's correspondent in Qatar, Paul Adams, says there are suspicions people are being made to carry suicide bombs.
It is the second apparent suicide car bombing in Iraq.
On 29 March, an Iraqi officer posing as a taxi driver detonated his car at an army checkpoint near the central city of Najaf, killing four US soldiers.
Iraqi President Saddam Hussein later honoured the officer and gave his family a large sum of money.
The Iraqi Government promised more suicide attacks.
Coalition troops were put on heightened alert after the first attack and there have since been incidents of soldiers firing on civilian vehicles that have approached checkpoints.
Eleven members of the same family were killed when troops fired on their vehicle near Najaf this week.
The family reportedly said they misunderstood coalition leaflets instructing them to flee to seek safety.