BAGHDAD -- Anti-American Shiite cleric Muqtada al-Sadr gave a "final warning" to the government Saturday to halt a U.S.-Iraqi crackdown against his followers or he would declare "open war until liberation."
A full-blown uprising by al-Sadr, who led two rebellions against U.S.-led forces in 2004, could lead to a dramatic increase in violence in Iraq at a time when the Sunni extremist group al-Qaida in Iraq appears poised for new attacks after suffering severe blows last year.
Al-Sadr's warning appeared on his Web site as Iraq's Shiite-dominated government claimed success in a new push against Shiite militants in the southern city of Basra. Fighting claimed 14 more lives in Sadr City, the Baghdad stronghold of al-Sadr's Mahdi Army.
Fighting in Sadr City and the crackdown in Basra are part of a government campaign against followers of al-Sadr and Iranian-backed Shiite splinter groups that the U.S. has identified as the gravest threat to a democratic Iraq.
Prime Minister Nouri al-Maliki, also a Shiite, has ordered al-Sadr to disband the Mahdi Army, Iraq's biggest Shiite militia, or face a ban from politics.
In the statement, al-Sadr lashed back, accusing the government of selling out to the Americans and branding his followers as criminals.
Al-Sadr, who is believed to be in Iran, said he had tried to defuse tensions last August by declaring a unilateral truce, only to see the government respond by closing his offices and "resorting to assassinations."
"So I am giving my final warning ... to the Iraqi government ... to take the path of peace and abandon violence against its people," al-Sadr said. "If the government does not refrain ... we will declare an open war until liberation."
U.S. officials have acknowledged that al-Sadr's truce was instrumental in reducing violence last year. But the truce is in tatters after Iraqi forces launched an offensive last month against "criminal gangs and militias" in the southern city of Basra.
The conflict spread rapidly to Baghdad, where Shiite militiamen based in Sadr City fired rockets at the U.S.-protected Green Zone, killing at least four Americans. U.S. officials say many of the rockets fired at the Green Zone were manufactured in Iran.
The Iranians helped mediate a truce March 30, which eased clashes in Basra and elsewhere in the Shiite south. But fighting persisted in Baghdad as U.S. and Iraqi forces sought to push militiamen beyond the range where they could fire rockets and mortars at the Green Zone.
At a news conference Saturday, Iran's ambassador to Baghdad said his government supports the Iraqi move, but the America siege of Sadr City "is a mistake."
"Lawbreakers [in Basra] must be held accountable ... but the insistence of the Americans to lay siege to millions of people in a specific area and then bombing them randomly from air and damaging property is not correct," ambassador Hassan Kazemi Qomi said.
Qomi warned that the American strategy in Sadr City "will lead to negative results for which the Iraqi government must bear responsibility."