Four soldiers were killed while their vehicle struck a roadside bomb south of Baghdad. They were on a combat patrol. A fifth soldier died on Saturday night when hit by another bomb attack, also in south of Baghdad.
Also on Saturday, two bombs exploded in a market in the northern Iraqi town of Muqdadiyah, killing two and wounding seventeen.
The second bomb was timed to explode just as the emergency services arrived at the scene of the first blast, police said.
US and Iraqi forces also fought an hour-long gunbattle with insurgents in Ramadi, a centre of Iraq's Sunni Arab-dominated insurgency, leaving four fighters dead and two Iraqi soldiers wounded, US officials said.
In the north Baghdad district of Azamiyah, gunmen attacked a police patrol, killing one officer, police said.
Two roadside bombs targeting Iraqi patrols exploded in other parts of the Iraqi capital, wounding three officers and five civilians.
A total of 2385 US soldiers have been killed in Iraq since the March 2003 US-led invasion toppled Saddam Hussein.
The bodies of 12 Iraqis - some of whom appeared to have been tortured - were found at four locations across the country.
Many of 11 bodies discovered in Baghdad were blindfolded and their hands and legs tied with rope. Another body was found floating in the river Tigris in Kut, 160km southeast of Baghdad.
The violence came as the Iraqi politicians appeared to have broken the deadlock over the formation of a national unity government.
Jalal Talabani, the Iraqi president, has asked tough-talking Shia leader Jawad al-Maliki to form a new government.
On Friday, 22 people died in violence across the country.