Seven US soldiers and an interpreter have been killed in insurgent attacks in Iraq, the US military says.
In western Baghdad, six US soldiers and their translator were killed by a bomb while patrolling the capital.
The troops' identities have been withheld until their families can be informed, the US military has said.
In a separate incident in Diwaniya, 130km (80 miles) south of Baghdad, one US soldier was killed and two injured when their vehicle was hit by a blast.
This brings the number of American soldiers killed since Friday to 15, and 76 so far this month, according to the AFP news agency.
May could prove to be one of the deadliest months for US forces in Iraq since the March 2003 invasion.
The BBC's James Shaw, in Baghdad, says roadside bombs remain the biggest threat for international forces operating in Iraq.
The troops killed in Baghdad were part of a unit which had spent the last week searching for weapons caches and bomb-making equipment in insurgents' safe-houses around the city, a statement released by the US military statement said.
In other violence, Iraqi police said five people were killed in two car bomb attacks in Baghdad.
Four people died when a car exploded in the mainly Shia area of Sadr City. Another person was killed and six injured in a blast near the interior ministry.
In western Iraq, a tanker lorry exploded as it was being driven towards a police checkpoint outside the city of Ramadi, killing a police officer and wounding several other people.
Police said they suspected chlorine gas was used in the attack.
The use of chlorine bombs in attacks has become more common since the start of the year.
On Wednesday, 32 people were killed and 50 injured in a suspected chlorine bomb attack on an open-air market in the village of Abu Sayda, in Diyala province.