Clashes early today between US forces and rebel Iraqi Shia cleric Moqtada al-Sadr's fighters in the holy city of Kerbala left at least eight Iraqis dead and 13 wounded.
Two US soldiers died in separate clashes near Baghdad.
Witnesses said some of the fiercest fighting in Kerbala took place only 100 metres from the city's shrines - some of the most sacred ground in Shia Islam - as Iraqi fighters launched rocket propelled grenades at US tanks moving into the area.
Hospital sources said at least eight Iraqis were killed in the skirmishes, the most recent since US forces deployed troops to the area to try to crush an uprising by the firebrand cleric's followers.
As clashes died down near dawn, the streets of the city, normally packed with tens of thousands of Shia Muslim pilgrims from Iran and elsewhere, were deserted.
Iraq's foremost Shia cleric, Grand Ayatollah Ali al-Sistani, called on US forces and Shia militia fighters to withdraw from the holy cities of Najaf and Kerbala today.
"It's permissible...to demand the withdrawal of all military vestiges from the two cities and allow the police and tribal forces to perform their role in preserving security and order," he said in a statement released by his office in Najaf.
A US military official said yesterday US forces had killed 51 guerrillas in fighting in the south, which has stretched occupying forces and illustrated the instability of Iraq six weeks before a formal transfer of power to Iraqis.
Elsewhere two US soldiers were killed in action in the volatile Anbar province, west of Baghdad. The province includes the flashpoint cities of Falluja and Ramadi.
Since last year's invasion, at least 571 US soldiers have been killed in action in Iraq, according to the latest Pentagon figures.