Baghdad // A new slogan has appeared in the past week on walls in eastern Baghdad and some southern Iraqi towns. Scrawled in paint, it is a simple and, to many Iraqis, chilling promise: "The Mahdi Army is returning."
On the buildings that line the streets and alleyways of neighbourhoods in the Shiite strongholds of north-eastern Baghdad, similarly foreboding messages admonish men against shaving their beards and women against forsaking the abaya for western clothing. Iraq's security forces quickly whitewash over the warnings, only for them to reappear elsewhere.
They appear to be a calling card of the Mahdi Army which, at the height of its influence in Baghdad after the US-led invasion of 2003, prohibited Iraqis from watching football on television on the ground that sport was against the teachings of Islam. It also operated death squads and fought US troops and Sunni militants with equal ferocity.
The feared Shiite militia was disbanded in 2008, but the prospect of its return has never been far from the minds of Iraqis. That possibility inched closer to reality when the Sadrist movement, which encompasses the Mahdi Army, won a prominent role in the government in last year's elections.
It is not only graffiti that has heralded a revival of the Madhi Army. Muqtada al Sadr, the cleric who leads the Sadrist movement, has openly threatened to deploy it.
In an address read out to thousands of his loyalists in Baghdad on Saturday, Mr al Sadr said he would revoke the orders freezing Mahdi Army activity and instruct the militia to resume military resistance against US troops if they remain in Iraq after the end of this year.
Under an agreement between Baghdad and Washington, all US military personnel are due to leave by the start of 2012, but US defence chiefs have hinted that they would like a sizeable force to remain beyond that point to prevent a security vacuum.
Hazem al Araji, a Sadrist official, underlined the point, telling Saturday's cheering crowd they were "all time bombs and the detonators in the hands of Muqtada al Sadr" unless American troops withdraw on schedule.
Abu Ali, a former Mahdi Army commander from southern Baghdad, said he and his men were now on standby.
"That speech was zero-hour for us to begin our preparations," he said. Abu Ali was released from prison about four months ago as part of a political deal with Mr al Sadr that secured a parliamentary majority for the prime minister, Nouri al Maliki, and thus a second term of office.
"We are on alert, and if, by 2012, the American forces don't leave, we will be at war with them," he said. "For now, we are watching and getting ready so that we are prepared for the end of the year."
If the order were given to resume the war, US forces would not be the only targets. "Disloyal" Iraqis who were assisting American troops would also be singled out, Abu Ali said.
He had no doubt the militia would be back in combat within eight months. "The Americans won't leave, they want to keep at least 10,000 soldiers here," he said. "We have sources inside the Iraqi government so we know what they are planning."
The Sadrists' office in Baghdad declined to comment, but a government official allied to the Sadrists' political wing said militia preparations were under way.
"In the past two weeks we've seen them start putting weapons arsenals up in their neighbourhoods and towns, and preparing new strongholds for operations in places like Ameen [in Baghdad] and Kut [a city in southern Iraq]," the official said. "It will not be good, it's going to cause problems for the community if they clash with the government forces and Americans again."
The official said hardline Mahdi Army leaders, many of whom had been released from jail or returned from exile in Iran, were motivated more by vengeance than by the desire to build a modern and prosperous Iraq.
"Their real goal is to take revenge against the army that defeated them," he said. Iraqi government forces routed the Mahdi Army in 2008 in a series of military clashes in which hundreds of militias fighters were captured, killed or fled to Iran.
"Unless he is careful, Muqtada al Sadr is going to lead the country back into battle and back into more problems," he said.
An Iraqi intelligence officer stationed in Kut, the administrative capital of Wasit province, 180km south of Baghdad, said security forces had information about Mahdi Army commanders trying to reactivate cells in the city and other southern provinces.
"At the moment we have no orders to move against them. We are waiting for national intelligence plans to be drawn up," he said. "There is a possibility of the Mahdi Army being reactivated in Kut. It's a concern."
The officer said slogans promising the militia's return had been painted on walls in towns in Wasit province, but that it was unclear who was behind it. "It might be the Sadrists, or it might someone else trying to make the people panic," he said.
Yacoub al Yasari, an independent political analyst who monitors the Mahdi Army, said he had "no doubt" it would return.
"The equation is simple: the Americans will not leave Iraq and they will clash with the Mahdi Army again," he said. "Certainly there will be new battles next year."
When the fighting resumes in earnest, he added, there will be plenty of fresh recruits.
"There is no shortage of people who will fight for them because a lot of young, poor Iraqis are very angry and disillusioned with the government and the Americans after all the years of failure."