Najaf - Hundreds of thousands of Iraqi Shi'as burned and trampled on US flags in the holy city of Najaf on Monday at an anti-American rally called by firebrand cleric Moqtada al-Sadr on the fourth anniversary of the fall of Saddam Hussein.
Large crowds of men, women and children holding Iraqi flags and anti-US banners massed in Najaf and the nearby city of Kufa to protest against what they said was an American occupation of Iraq.
The rally is seen as a show of strength for the cleric who has not been seen for more than two months, since the launch of a security crackdown in Baghdad aimed largely at reining in his militiamen accused of killing Sunni Arabs.
The US military has said he has gone to Iran but his aides deny the claims and insist he is still in Iraq.
Security was tight in Baghdad, where four years ago on Monday a giant bronze statue of Saddam was torn down, dramatically symbolising the fall of his regime.
A 24-hour vehicle curfew was in place and all main roads and bridges were deserted as people remained indoors for fear of attacks.
Jubilant Baghdadis who welcomed the invading US troops on April 9, 2003, now blame the rampant bloodshed and chaos on what even some of Iraq's most senior leaders brand an unwanted occupation.
The Shi'a demonstrators are marching from Kufa to Najaf's central Sadrain Square where top aides of Sadr - regarded by the Americans as the most dangerous threat to stability in Iraq - are expected to address the crowds.
Hundreds of banners saying "Down with Bush, Down with America" were carried by protesters as Iraqi police and soldiers guarded checkpoints in and around Najaf and Kufa.
Many people, draped in Iraqi flags, set US flags ablaze and some trampled on and struck US and Israeli flags painted on the ground with their shoes, an act considered one of the worst insults in Arab culture.
"In four years of occupation, our sons have been killed and women made widows," cried Ahmed al-Mayahie, 39, a Shi'a from the southern city of Basra.
"The occupier raised slogans saying Iraq is free, Iraq is liberated. What freedom? What liberation? There is nothing but destruction. We do not want their liberation and their presence. We tell them to get out of our land."
Lawmaker Falah Hassan Shanshil from Sadr's parliamentary bloc said: "This crowd has come to reject the American occupation and demand its withdrawal."
Some Sunni religious groups were also seen participating in the rally.
It was not known whether Sadr himself would address the crowds.
The cleric, who launched two bloody rebellions against US forces in 2004, is known for his anti-US stance and has emerged as a powerful force in the Shi'a-led government.
His political bloc has 32 lawmakers in the 275-member parliament and six ministers in Prime Minister Nuri al-Maliki's embattled government.
On Sunday, he reiterated his call to unite against the Americans and end fighting that erupted on Friday between his militiamen and security forces in the central city of Diwaniyah.
"He appeals to the Iraqi army and the Mahdi militia not to fall into America's trap by fighting in Diwaniyah," said a statement issued by the cleric's Najaf office on his behalf.
Sadr urged local security forces not to support the "occupier because it is your enemy."
"Iraq has had enough bloodshed. The occupation forces led by the biggest evil, America, is working to sow dissent either directly or through its agents."
On April 9, 2003, US Marines pulled down the giant statue of Saddam by a rope around the neck, in a premonition of his hanging in December for crimes against humanity.
But gone are the euphoric cheers of "Good, Good, Bush" praising US President George Bush for ousting the regime. Angry chants of "Down with Bush" are a frequent background to brutal Shiite and Sunni sectarian strife.
About 80 000 US and Iraqi troops are now patrolling the capital's streets where although daily execution-style killings are reported to be falling, high-profile car bombings continue unabated.
Since the March 2003 invasion, tens of thousands of Iraqis have died in insurgent attacks and sectarian violence.
The four years have also been brutal for US forces.
On Monday, the military reported the deaths of six more soldiers in a series of attacks, taking its toll for April alone to 27 and 3 275 since the invasion, according to an AFP count based on Pentagon figures.