The demonstrators took to the streets of Najaf, 160 kilometers (100 miles) south of Baghdad, in response to an earlier call for mass rallies by an influential radical Shiite cleric, Muqtada al-Sadr, who is known for his strident anti-American views and strong support of an immediate withdrawal of coalition troops from Iraq.
"We called upon people to unite in a demonstration to demand the pullout of occupation forces from Iraq," a leader of Sadr's bloc in parliament, Saleh al-Ukaili, told RIA Novosti Sunday.
Security has been tightened around Najaf, with cars banned from entering the city for 24 hours.
Iraqi police and troops lined the road from the neighboring city of Kuba, where al-Sadr's headquarters are located, to provide security for a march of protesters who wrapped themselves in Iraqi flags and shouted anti-American slogans.
An al-Sadr spokesman is expected to address the demonstrators with the latest statement issued by the radical cleric, who reportedly left Iraq for neighboring Iran following a Baghdad security crackdown that began in February.
Four years ago, U.S. Marines and the Army's 3rd Infantry Division captured the Iraqi capital 20 days into the U.S.-led invasion that put an end to the rule of the former Iraqi dictator Saddam Hussein.
In late March, the U.S. Senate adopted a budget bill envisioning a staged withdrawal of all combat units of the U.S. Armed Forces from Iraq by March 31, 2008.
However, President George Bush said that he will veto any draft law demanding the withdrawal of troops from Iraq, warning that America cannot afford to be defeated in Iraq and that Congress should not impose any date for a withdrawal, arguing that it would be catastrophic for the U.S.
