In his first speech since returning from almost four years of self-imposed exile in Iran, the 37-year-old cleric whose Shiite militias once ruthlessly pursued U.S. troops and terrorized Iraqi Sunnis stopped short of explicitly urging violence against Americans. But he left open the possibility that some 50,000 U.S. troops set to leave Iraq at the end of this year could be targeted.
"Let the whole world hear that we reject America. No, no to the occupier," al-Sadr said during his 35-minute speech in Najaf, a holy Shiite city about 100 miles south of Baghdad. "We don't kill Iraqis - our hands do not kill Iraqis. But we target only the occupier with all the means of resistance," he added.
"We are still resisters and we are still resisting the occupier militarily and culturally and by all the means of resistance."
Al-Sadr has long branded the U.S. military as occupiers in Iraq, and Washington considers him a security threat. Yet after winning 40 seats in March parliamentary elections - and taking eight top leadership posts in the new government - al-Sadr's political muscle makes him a force that cannot be ignored.
Addressing an adoring and frenzied crowd of thousands, al-Sadr called the U.S., Israel and Britain "our common enemies."
"Maybe during the past few days and months, we forgot the resistance and the expel of the occupier as we were busy with politics," al-Sadr said. "Our aim is to expel the occupier with any means. The resistance does not mean that everyone can carry a weapon. The weapon is only for the people of the weapons" - fighters.
U.S. Embassy spokesman David J. Ranz brushed off al-Sadr's remarks. "We listened to the speech, but heard nothing new," Ranz said.
A security agreement between Washington and Baghdad requires all U.S. forces to be out of Iraq by the end of the year. Although both al-Maliki and the Obama administration have maintained the roughly 50,000 U.S. troops will leave by then, officials in both nations have acknowledged that Iraq is not yet ready to protect its borders from possible invasion. That's led to widespread speculation that al-Maliki ultimately will ask a small number of American forces to remain.
Al-Sadr said Saturday that would be unacceptable, but asked his followers to let the government carry out its plan for the troop departure.
"The new government must work to get the occupier out of the country in a suitable way," he said. "We heard the government pledge this and we are waiting for it to honor its word."
Al-Sadr rose to power after the March 2003 invasion and has since been revered by poor Iraqi Shiites. His Mahdi Army gunmen were a formidable foe of American troops and Iraqi government forces between 2004 and 2008, but al-Sadr fled to Iran in 2007 under threat of arrest for allegedly killing another cleric. Although absent from Iraq for four years, he has maintained strict control over the political and military wings of his movement from his base in Iran.
It's not clear whether al-Sadr will remain in Iraq or return to Iran. Followers and detractors hung on his words, delivered outside his ancestral home, for signs of where he plans to take his political movement.
"We are like crazy people who lost their father for a while," said shop owner Samir Atwan, who closed his store in the Baghdad slum of Sadr City to join the black-clad thousands who thronged outside the cleric's ancestral home in Najaf, 100 miles south of the capital.
Atwan said he slept on the street in Najaf for three days in hopes of seeing al-Sadr. "All these people left their jobs and their shops," he said. Nearby, a blind man led a crowd of young men who waited hours in the cool January morning amid cries of "Yes, yes, to our leader."
It was only with al-Sadr's support - and with the blessing of Iran - that Prime Minister Nouri al-Maliki was able to muster enough support from former opponents to win a second term in office after his political party fell short in the March elections. The alliance was surprising to Iraq's political observers, and especially to Sadrists who were crushed by al-Maliki's security forces in Baghdad and the southern port city of Basra.
But Iranian leaders pushed for the detente that gave al-Sadr new sway over al-Maliki and led Iraq's Sunni minority to fear they would remain without a voice in the new government.
In the Sunni-dominated Baghdad suburb of Azamiyah, Majid al-Adhami watched with apprehension the speech he described as "directed to his followers rather than to the Iraqi people."
"He came from abroad with a message from his masters that he will continue what he and his followers used to do," said al-Adhami, 57, a retiree and father of five. "He's saying now that I used to control the street and now I'm controlling both the street and politics."
Kurdish lawmaker Mahmoud Othman said after the speech that al-Sadr appeared to be seeking more political influence without having to resort to violence.
"If he means violence, then this will complicate the political process, destabilize Iraq, embarrass al-Maliki and prevent al-Sadr from gaining more influence," Othman said. "There is nothing to gain from violence."
Al-Sadr's use of the word "resistance," he said, was meant to signal that he and his followers are not going away.
By Associated Press Writers Rebecca Santana and Bushra Juhi; AP's Lara Jakes, Sinan Salaheddin and Qassim Abdul-Zahra contributed to this report.