Tens of thousands of Iraqi Shi'ite Muslims marched to chants of "No to America" today and an aide to their spiritual leader warned of bigger protests if Washington rejected the majority group's call for elections .
Iraq's US governor Mr Paul Bremer headed for Washington for talks on Friday with President George W. Bush.
They are likely to discuss mounting tension over a US plan to hand sovereignty to an Iraqi administration by July without holding the direct elections that the long-oppressed Shi'ites are demanding.
In the latest violence, three Iraqis were killed and one was injured when a landmine exploded under a bus in Tikrit, Saddam Hussein's mostly Sunni Muslim home town, the US military said.
Highlighting fears of ethnic and religious bloodshed in the wake of Saddam's overthrow, a leader of the small Turkmen minority vowed a fight to the last drop of blood over a Kurdish drive to carve out an autonomous homeland in the north.
In the Shi'ite south, tens of thousands protested in Iraq's British-controlled second city of Basra in support of Ayatollah Ali al-Sistani's call for elections.
It was a show of strength behind the top Shi'ite cleric who an aide said could issue an edict against any unelected body.
"If (Sistani) issues a fatwa (or edict) all the Iraqi people will go out in protest marches and demonstrations against the (U.S.-led) coalition forces," the aide, Ayatollah Mohammad Baqer al-Mohri, told reporters in Kuwait.
Mohri earlier told Abu Dhabi television such a fatwa could undermine the legitimacy of any unelected Iraqi administration.
Sistani has objected to the US plan for a transitional assembly to be selected by regional caucuses rather than a popular election. The assembly will select an interim government that is due to take over sovereignty by the end of June.