By Adam Brookes
BBC News, Baghdad
Did the government do a deal with Moqtada Sadr?
The fighting between Shia militias and Iraqi and coalition forces in Basra last week led to hundreds of deaths - more than three hundred by some counts.
Yet what the Iraqi Prime Minister, Nouri Maliki, declared to be "a fight to the end" concluded with an accommodation, the details of which remain unclear.
As the dust settles in Iraq's second city, different versions of what actually took place there last week are emerging.
A military operation - overseen by Mr Maliki - was intended to "cleanse" the city of militia activity.
But resistance by fighters of the Mehdi Army, loyal to the cleric Moqtada Sadr, was unexpectedly fierce.
Mr Maliki returned to Baghdad this week, calling the operation a success.
It is a claim that is being widely disputed in Iraq.
The Mehdi militiamen withdrew from the streets after six days of fighting, but they appear to have taken their arms with them, defying Prime Minister Maliki's initial demand that all militia-held medium and heavy weapons be surrendered.
The political leadership of Iraq is saying that there was no deal with the Mehdi militia to stop the fighting.
On Thursday Mr Maliki insisted he had not ordered negotiations with Moqtada Sadr.
And a source close to the prime minister says that Moqtada Sadr's order to cease fighting came at the instigation of Iran.
The fighting began with operations against militias in Basra
The source said that as the bloodshed in Basra began early last week, Moqtada Sadr tried to telephone Prime Minister Maliki from Qom, in Iran - and the prime minister refused to take his call.
But a delegation from the United Iraqi Alliance, the parliamentary bloc that supports Mr Maliki, flew to Tehran, where they told representatives of the Iranian leadership that Iran's involvement in stirring up the militia violence was unacceptable and would have to stop, the source said.
They pointed out that Iranian munitions were being used in the fighting.
The Iranian leadership, according to the source, then brought Moqtada Sadr to Tehran.
There, late on Saturday night, he crafted the statement that would order his Mehdi Army militiamen off the streets, the source said.
In this version of events, the Iraqi prime minister retains the ability to deny entering talks with Moqtada Sadr. In effect, it appears to have been done for him, with Iranian influence brought to bear.
Moqtada Sadr's organisation, for its part, says its leader chose to order his militiamen off the streets for the sake of "Iraqi unity". His militiamen fought Iraqi troops to a standstill in parts of Basra.
British and American support - including logistics, air strikes and artillery fire - was organised hurriedly to help break their resistance.
American air strikes were called in to target snipers
Moqtada Sadr has called for a million people to take to the streets across Iraq on 9 April - supposedly to protest against the coalition military presence in Iraq.
But a large turnout would also serve to demonstrate at home as well as abroad the strength of his following, even after the Basra confrontation. The United States ambassador to Iraq, Ryan Crocker, on Thursday reinforced the view that Iran was directly supporting the activities of the Mehdi Army militia through the week.
Rockets, he said, that had landed inside the Green Zone were manufactured in Iran, some of them as recently as last year.
"How does he know? We have the tailfins," he said.
Ambassador Crocker was insistent that the operation had shown the Iraqi armed forces in a positive light, even if some objectives were not achieved.
"There is still a major problem in Basra," he said, "but in terms of decision, resolve and ability, they did it themselves and they got in the fight."
He pointed to what he said were tangible gains for the Iraqi government - "thousands" of people, at the behest of tribal leaders, were signing up to be security volunteers, he said.
Iraqi forces took the lead in the Basra operation
And the vital port facilities of Um Qasr were now completely in the hands of the Iraqi security forces, he added.
The armed forces had demonstrated in Basra that they were growing in strength and confidence:
"One thing [the Basra operation] tells us is that the Iraqi Security Forces will increasingly be in the lead."
Earlier in the day, Mr Maliki conceded that elements of the military had not performed well, and were being investigated.
His comments echoed those of a US military spokesman on Wednesday, who said some of the soldiers were not "up to the job".
Mr Crocker will soon board a plane back to Washington, where, together with the commander of coalition forces, General David Petraeus, he will testify before Congress on the situation in Iraq.
He will no doubt be questioned about the competence of Iraq's military and its ability to take over security responsibilities from US troops - it appears he will use the Basra operation as evidence that the Iraq's soldiers are performing.
But the Ambassador is a man with few illusions, and he conceded that the Basra operation did not go as planned.
"I did not expect a major battle from day one," he said.
The Basra operation, it appears, is an empty vessel - it can be filled with any interpretation you choose.
For the Iraqi government and the Americans it is evidence of the growing confidence of the state to exercise power, even though Mr Maliki and Ambassador Crocker have said they were taken by surprise by the scale of the resistance.
For the movement of Moqtada Sadr it was a demonstration of power across south and central Iraq - even though its militia ended up withdrawing.
The role of Iran in the outcome appears important, but is still opaque.
The one conclusion which, so far, can be drawn unequivocally - Iraq is a place where violence can flare and spread exceedingly quickly. The security gains of recent months, as Ambassador Crocker and General Petraeus have readily conceded, remain fragile.