Karbala, Iraq ? Swaying and chanting, some slashing their bodies and drawing blood, an estimated 1 million Shiite Muslims marched to this city’s holy shrine Tuesday to mourn one of their most revered saints — but also to celebrate their new freedoms after years of repression by Saddam Hussein’s regime.

Pilgrims, many limping from long journeys in 90-degree heat, pressed up against each other on roads. U.S. troops were largely out of sight, with a few members of the U.S.-backed Iraqi National Congress at checkpoints.

The large turnout attests to the power and potential of Iraq’s majority Shiite community, which despite bitter internal differences was able to pull off the event on short notice and thus far — the pilgrimage ends Thursday — without violence.

Two prominent figures in the Shiite clergy are Grand Ayatollah Ali Hussein al-Sistani, who is Iraq’s top Shiite cleric and heads the Hawza al-Ilmiya, a center of Shiite learning in the holy city of Najaf; and Muqtada al-Sadr, the son of al-Sistani’s slain predecessor.

“All the religious leaders, Sistani and Sadr, united to make it (the pilgrimage) successful and had it not been for this unity, it would have failed,” said Sheik Sadeq Jaafar al-Tarfi, who is affiliated with the Hawza. “After the regime collapsed we were faced with the problem of a political vacuum. So we moved in a specialized and organized way to face this problem.”

He said the Hawza sent in thousands of volunteers to manage security and traffic. American troops were ready with food and water; it wasn’t needed.

The United States hopes to work with Shiites to form a new government without resorting to a Shiite theocracy like the one in neighboring Iran — a balancing act that will test the skills of retired U.S. Lt. Gen. Jay Garner, who is overseeing Iraq’s postwar reconstruction.

Throngs of Iraqi Shiite muslim pilgrims celebrate as they circle the Imam Hussein holy shrine in Karbala, Iraq. For the first time in decades, Shiite Muslims in Iraq are able to gather in the Shiite holy city of Karbala to mark the end of the 40-day mourning of the death of one of their most important saints, Imam Hussein.

Shiites were long suppressed by Saddam’s ruling Sunni minority. Since the fall of Saddam’s regime, Shiites have been setting up local administrations, and religious leaders have emerged as key sources of political power, especially in southern Iraq. It is unclear whether clerics will be ready to transfer power to a new government.

Senior Shiite clerics insist they want to share power with Iraq’s other communities, particularly Sunnis and Kurds. But many Shiites — from secularists to fundamentalists — have also shown a deep mistrust of U.S. efforts in Iraq.

There was anti-American sentiment among the pilgrims Tuesday. Some held signs that said “Bush Saddam” and “Down USA.”

Shiite clerics attending the gathering called on their followers to use peaceful methods to force the Americans to go home.

“Public opinion is building against the Americans, and we must try to find a peaceful way to force America to leave,” said Sheikh Abdul Mehdi al Salami. “If peaceful demonstrations don’t work, we will have to see what to do when the time comes.”