The soldiers were on a combat patrol when a roadside bomb exploded near them on Thursday, the military said in a statement. Shortly after the blast, insurgents attacked with small arms fire and rocket-propelled grenades, it said.
All seven wounded soldiers were evacuated to a military hospital, and one has since returned to duty, the military said. The victims' names were withheld pending family notification.
The deaths brought to 99 the number of U.S. troops who have died in Iraq this month, according to an Associated Press count. The toll for the past three months - 329 - made it the deadliest quarter for U.S. troops in Iraq since the war began in March 2003.
At least 3,576 members of the U.S. military have died since then, according to AP figures. The number includes seven military civilians. At least 2,936 died as a result of hostile action, according to the military's numbers.
Meanwhile, radical cleric Muqtada al-Sadr postponed a Shiite march to a bombed shrine north of Baghdad that was scheduled for July 5, an aide said.
"Muqtada al-Sadr has decided to postpone the march to Samarra for several reasons, including the government's inability to secure the route and many officials' appeals for a postponement," said Sheik Asad Al-Nassiri, an aide to the cleric. He made the announcement during a Friday sermon in nearby Kufa.
Sunni organizations and government officials had urged al-Sadr to cancel the march to the Askariya shrine in Samarra, which was bombed for a second time earlier this month, fearing it would escalate sectarian violence that already has claimed thousands of lives.
Al-Sadr had said the march was aimed at bringing Shiites and Sunnis closer together and breaking down the barriers imposed by the Americans and Sunni religious extremists.
Also Friday, the British military issued a statement saying all of its bases came under attack from mortars or rockets in the past 24 hours, but there were no casualties or damage.
Britain maintains a force of about 5,500 troops based mainly on the fringes of Basra, Iraq's second-largest city, 550 kilometers (340 miles) southeast of Baghdad.
In other violence, Iraqi police said a suicide car bomb exploded at Iraqi army post north of Baghdad, destroying the building and igniting a fire. There was no immediate word on casualties.
The blast went off at a railway station in Mishada, a town 30 kilometers (20 miles) north of the capital, an officer said on condition of anonymity because he was not authorized to release the information.
In other developments, Iraqi police said a bomb exploded under an oil pipeline south of Baghdad on Friday, spilling crude oil and sparking a huge fire.
The explosives were planted under a stretch of pipeline in the Mowehlah area of Haswa, a town 50 kilometers (30 miles) south of the Iraqi capital, a police officer said on condition of anonymity because he was not authorized to release the information.
The pipeline transmits crude oil from Iraq's southern oil fields to the Dora refinery in Baghdad.
The blast ignited a huge fire around 5 a.m., the officer said. By midday, firefighters were still struggling to extinguish the flames, which were fueled by a continuing leak of oil from the pipeline, he said. Workers also were looking for a way to temporarily cut off the oil flow, until a repair could be made, the officer added.