At least 13 other Iraqis were killed in other incidents, including a roadside bombing in Tikrit, clashes between Polish troops and Shiite militiamen in Karbala and US raids in Sadr City.
Meanwhile, Paul Bremer, who heads the US-led mission, travelled to Fallujah to join what have been described as increasingly futile negotiations aimed at ending the US military siege of the rebel-held city.
The five US solders were killed, when two rockets were fired from a truck and slammed into the base in Taji, 20 kilometres north of Baghdad, Air Force Lieutenant Colonel Sam Hudspath said. US helicopter gunships then destroyed the truck.
Six soldiers were wounded in the attack, three of them critically, the military said.
The deaths, along with that of a Marine announced yesterday, brought to 107 the number of US troops killed in Iraq since the beginning of April. Since March 2003, 715 service members have died in the country.