The US military said in a statement on Tuesday that the five fighters died on Monday in Ramadi, 115km west of Baghdad, in a series of shootings that began when marines discovered them trying to plant bombs in a hole used in the past to conceal explosives.
The incident occurred one day after army snipers killed eight people who were also trying to conceal explosives in Ramadi, capital of Iraq's most volatile province, al-Anbar, the US military added.
In other news, a senior member of the Iraqi police in Basra, Colonel Mahmud Qassim, was killed on Tuesday when a roadside bomb exploded near his convoy south of the city, police said.
Another police officer died in the attack.
Police officer killed
Elsewhere, a roadside bomb killed a police officer and wounded three others on Tuesday near the northern oil city of Kirkuk, police said.
The same day Iraqi police found six handcuffed corpses in a water-treatment plant, police said.
At least 2054 US soldiers have
died in Iraq since March 2003
One civilian was killed when fighters opened fire in the notorious al-Dura district in the south of the capital.
A car bomb exploded near Mustansiriyah University, killing one person and injuring another.
An Iraqi police officer, holding the rank of brigadier, has been killed and four of his guards injured in an explosion hitting their patrol in Abu al-Khusaib area.
On Monday evening, four US soldiers died in a car bombing in southwestern Baghdad, the US military said.
A civilian translator was also killed in the attack.
The US military released few details about the deaths of the four Americans and their translator in the car bombing.
They were members of the US army's Task Force Baghdad and were killed at about 5pm on Monday, the military said.
Their deaths brought to at least 2054 the number of US military personnel who have died since the beginning of the Iraq war in March 2003, according to an Associated Press count.
Roadside bombs have become the major killer of US forces in Iraq, accounting for most of the 96 deaths among US service members in Baghdad last month.