Three US soldiers were killed by a roadside bomb in Baghdad, and a marine was killed in Iraq's western Anbar province yesterday, the US military said today.
It said the three soldiers in Baghdad died when their vehicle was hit by a roadside bomb in the east of the capital.
The marine in Anbar died due to "enemy action", the military said.
The military also announced this morning that a soldier had died in a non-combat-related incident north of Baghdad.
US forces have been searching Baghdad for a missing US soldier of Iraqi origin who was kidnapped 10 days ago after going to visit relatives, including his Iraqi wife.
Troops have also been conducting more visible patrols in Baghdad in an effort to clamp down on sectarian violence.
October was the most deadly month for the US military in Iraq in nearly two years, with at least 105 killed, raising the pressure on President Bush ahead of elections next week that could see him lose control of Congress.