Iraq's Moqtada al-Sadr warns Mehdi Army ready to fight
Iraqi cleric and militia leader Moqtada al-Sadr has threatened to take up arms against US troops unless they leave the country by the end of the year.
In a rare interview, he told the BBC he believed US forces would not stick to an agreement to withdraw from Iraq.
The US still has about 46,000 troops in Iraq, due to have withdrawn by January 2012.
On Thursday, tens of thousands of the cleric's supporters rallied in Baghdad, calling for the Americans to leave.
The Pentagon has been pressing the Iraqi government to decide quickly whether it will ask some to stay on beyond the deadline.
In Sadr City, Moqtada al-Sadr's Baghdad stronghold, his supporters marched in military formation, their boots trampling on the flags of the US, UK and Israel.
These were members of the Mehdi Army, a Shia militia which fought a bitter sectarian war in the aftermath of the US-led invasion.
They sported a new uniform - gone were the trademark black shirts of the past. Instead, they wore the colours of the Iraqi flag - red, white and black - with Allahu Akbar (God is Great) emblazoned across the middle.
It was an attempt to turn a divisive sectarian past into a broader nationalist appeal.
The message seemed to say - we are in this together, Iraqi Shia or Sunni, against the Americans.
There were no weapons in evidence but, speaking to the BBC, Moqtada al-Sadr made it clear that the Mehdi Army was still a fighting force to be reckoned with.
"I know that the Iraqi government is under a lot of pressure from the American occupiers, to allow them to stay in Iraq," he said in the holy city of Najaf.
"If the Americans don't withdraw, we will re-activate the Mehdi Army. At the moment their activities are frozen, but if the Americans stay, that will change.
"We are resisting, we are targeting their bases, their soldiers and their vehicles as long as they are here in Iraq."
Until January, Moqtada al-Sadr had spent most of the past two years in self-imposed exile in Iran, squeezed out by a combined US and Iraqi military effort.
But last year's election marked a turning point in his fortunes. His party did better than expected in the poll, and now he is back in Iraq, with seats in parliament and a growing sense of confidence.
The Americans still have thousands of troops in Iraq and, nervous of Iran's growing influence, they have made it clear they would like to keep some of them in the country beyond the end of this year.
But, in order for that to happen, they must be invited to stay by the Iraqi government. And Moqtada al-Sadr seems determined to portray himself as the man who pushed them out.