Shiite leader Moqtada al-Sadr said on Saturday that his supporters will resume their resistance to U.S. forces in Iraq if they do not leave as scheduled by the end of the year.
"If the Americans don't leave Iraq on time, we will increase the resistance and restart the activities of the Mahdi Army," Sadr said in a fiery statement read by a spokesman to thousands of followers in Mustansariyah Square in northeast Baghdad.
He was referring to his militia which mounted repeated uprisings against U.S.-led forces in Iraq before he stood it down in August 2008.
"Out, out America," spokesman Salah al-Obeidi repeatedly warned, speaking on the eighth anniversary of the day when Iraqi dictator Saddam Hussein was ousted and Baghdad fell to US-led forces.
The Americans must leave, "now, now, now", he warned, reading the statement from Sadr, who divides his time between the central shrine city of Najaf and neighboring Iran. "Out, out America," he added.
Forces could stay beyond 2011
The message from Sadr came a day after U.S. Defense Secretary Robert Gates ended a two-day visit to Iraq, in which he said U.S. forces could stay on beyond 2011 in some numbers, if asked.
Gates asked Iraqi politicians to speed up their request if they wanted some troops to remain.
"My basic message to them is (for us to) just be present in some areas where they still need help. We are open to that possibility," the Pentagon chief said, speaking at a U.S. military base in northern Iraq.
"But they have to ask, and time is running out in Washington," Gates said, after meetings with Prime Minister Nouri al-Maliki, President Jalal Talabani and Massud Barzani, president of the autonomous Kurdistan region in the north.
But Sadr's statement warned that U.S. forces must leave, "to the last soldier and base".
Nearly 50,000 American troops still remain in Iraq, down from a peak of more than 170,000 after the invasion, and ahead of the planned full withdrawal at the end of this year.
The debate over the future of U.S. troops in Iraq comes as local forces struggle to improve intelligence and logistics capabilities that could help them vanquish insurgency.
The deadly abilities of insurgent groups like al-Qaeda were evident on March 29 when gunmen used car bombs and explosive belts to attack a provincial council headquarters in the northern city of Tikrit, killing close to 60 people.
Sadr, who is said to be in his 30s, gained wide popularity among Shiites in Iraq in the months after the U.S.-led invasion of 2003 and in 2004 his Mahdi Army militia battled U.S. troops in two bloody conflicts.
He was identified by the Pentagon in 2006 as the biggest threat to stability in Iraq.
His militia became the most active and feared armed Shiite group, and was blamed by Washington for death-squad killings of thousands of Sunnis.
But in August 2008, Sadr suspended the activities of his Mahdi Army, which once numbered in the tens of thousands, following major U.S. and Iraqi assaults on its strongholds in Baghdad and southern Iraq in the spring.
Following the ceasefire, U.S. military commanders said his action had been instrumental in helping bring about a significant decrease in the levels of violence across Iraq.
The fiery anti-American cleric, who has been pursuing religious studies in the Iranian holy city of Qom, is the son of revered Grand Ayatollah Mohammed Sadiq al-Sadr.