The soldiers died in attacks on Monday during combat operations in the volatile western Iraqi city, 70 miles west of Baghdad, the military said.
The victims were U.S. Army soldiers attached to the 2nd Marine Division, II Marine Expeditionary Force.
The names of the victims were not released.
Meanwhile in Mosul a suicide car bomber rammed a U.S. convoy, killing four Americans and wounding two others.
A U.S. official said the victims were a Diplomatic Security agent and three private security guards attached to the U.S. Consulate in Mosul, Iraq's third largest city.
Two weeks ago, a roadside bomb killed four private American guards who worked as security agents for the Bureau of Diplomatic Security in Basra.
Al Qaeda claimed responsibility for that attack.
In other developments:
After the day of violence in Basra on Monday, British authorities said their soldiers were being held illegally and that their captors had refused an order from Iraq's interior minister for their release. The commander of the operation to free the pair sought to minimize the extent of destruction at the jail.
"Minor damage was caused to the prison compound wall and to the house in which our two soldiers were held," said Brig. John Lorimer, commander of the 12 Mechanized Brigade.
Daylight pictures from the jail Tuesday showed a concrete wall broken through, several cars crushed — apparently by armored vehicles — an a number of prefabricated structures demolished.