Baghdad's vast and impoverished Sadr City district was near boiling point after a deadly clash with US troops that many Shiite Muslims here saw as an assault on their cherished faith.
"We are ready to defend our religion," said Sheikh Qais Al-Kazali, deputy secretary to the district's firebrand anti-occupation Shiite cleric Moqtada Sadr.
"I hear there are people here who are preparing mines and suicide explosive belts, and others are ready to use rocket-propelled grenades. We have difficulties controlling the people," he said.
On Wednesday, US troops fired into a crowd of thousands of demonstrators in Sadr City, killing one person, after they were allegedly targeted by an RPG. The protest was sparked by an American helicopter that apparently tried to remove a black religious flag from a communications tower.
"What do they have against our flag? This is an insult to Shiite Muslims," said an elderly man, who did not give his name, dressed in a traditional Arab robe and headdress.
"The Americans, they are playing with fire. Do they want the sleeping lion to wake up? Yesterday, he reared his head," said an unemployed youth, Abbas Jamal.
The incident was the first armed clash between US forces and Shiites in Baghdad since the war to oust Saddam Hussein.
Iraq's Shiites make up some 60 percent of the 25-million population but were long oppressed by Saddam's Sunni Muslim elite.
Since the dictator was ousted by the US-led coalition in April the Shiites have been flexing their political muscle and are now courted by the Americans who see them as central to hopes for stability in the war-torn country.
The US army was quick to apologise to Shiite clerics in Sadr City over Wednesday's incident.
"There has been an apology from commanders on the ground," Lieutenant General Ricardo Sanchez, the commander of coalition ground forces in Iraq, told reporters Thursday.
The northeast Baghdad neighbourhood of two million was renamed after cleric Moqtada Sadr's father, the grand ayatollah Mohammed Sadeq al-Sadr, and the father's cousin, who were assassinated by the old regime.
But there was little support there Wednesday for a call on Iraq's top Shiite religious authority, the Hawza, attributed to Saddam, to "proclaim jihad (holy war) so that all the Iraqi people are united against the occupation."
"It's not Saddam who can call for jihad," said Abbas Jamal. "We don't follow orders from the US or from Saddam. Only from the Hawza."
"If there's a fatwa (religious edict) from the Hawza, there's no doubt, we will fight," said garage owner Ali Khalaf.
Most observers here agree that there would be bloody chaos if the Hawza were to instruct Iraqi Shiites to rise up against the occupying forces.
The Hawza, based in the Iraqi holy city of Najaf, south of Baghdad, is Iraq's top Shiite religious authority.
Saddam's purported message also praised Grand Ayatollah Ali al-Sistani, regarded as the most influential of four top Hawza clerics.
Though viewed by US officials as a crucial force for moderation in post-war Iraq, he has voiced unease at the occupation and opposed plans for the US-backed interim Governing Council to draw up a new constitution for the country.
On Thursday a top aide to Sistani said the ayatollah categorically rejected Saddam's call.
In Sadr City, Sheikh Kazali issued a stark warning to coalition forces.
"If the Americans promise not to come back to Sadr City nothing will happen. If they do the situation will be worse," he said.