Shopkeepers opened fire Friday on mobs of looters in the Iraqi capital, which has been marred by sporadic clashes with small pockets of pro-Saddam Hussein resistance since the collapse of the strongman's government.
US marines patrolled checkpoints throughout Baghdad, where no attacks against coalition troops were reported Friday morning.
But shopkeepers in central Baghdad opened fire on looters for the first time since US troops entered the city, and the widespread chaos left 25 people injured.
"We want the law to rule and if the Americans don't defend us then we'll defend ourselves with our own weapons," said merchant Khazen Hussein.
US troops, who say they are still involved in a military campaign and do not have the capacity to maintain law and order, have not intervened to stop the looting.
In Al-Rasafi market, merchants fired pistols in the air outside a seven-storey garment store, while at Al-Arabi market shopkeepers fired Kalashnikov rifles toward approaching looters.
Young people were also seen with iron bars running after potential thieves.
Baghdad has seen rampant looting since US troops rolled in Wednesday and the two-and-half-decade authority of Saddam Hussein crumbled.
Almost everything has been considered fair game, from the luxury homes of senior Iraqi officials to European diplomatic missions and former state institutions that once inspired fear.
Twenty-five people were admitted to Baghdad's Al-Kindi hospital on Friday after suffering gunshot wounds in clashes during the looting.
But the hospital, Baghdad's largest, can provide little help as it has been ransacked itself.
"The situation is chaotic and catastrophic," Peter Tarabula, medical coordinator for the International Committee of the Red Cross (ICRC) here, said after an ICRC team inspected the hospital.
All staff have fled Al-Kindi hospital with the exception of two doctors who administer first aid but do not carry out operations.
"The doctors have all left," said nurse Jawad al-Jabiri.
Few patients remain at the hospital since the looting Thursday, in which armed men stole two ambulances and medicine from the facility.
Shiite Muslim fighters from the southern city of Najaf have now set up camp at the hospital and are posted at all the exits.
The fighters are led by Sheikh Abbas al-Zubaidi, who has donned a white doctor's gown over his traditional robe.
Scenes of widespread chaos and near anarchy in Iraqi towns prompted UN Secretary General Kofi Annan on Thursday to demand the United States and Britain respect their international obligations as occupying forces and maintain order.
Elsewhere on the ground, a US soldier died in a suicide bombing in north Baghdad late Thursday after marines came under heavy fire from pro-regime pockets of resistance.
A US military source said the attack had taken place in Saddam City, an impoverished northern suburb home to two million people, mostly Shiite Muslims.
It was the first suicide attack against American forces since they captured Baghdad amid scenes of jubilation and looting, and raised fresh doubts about how firmly coalition forces held the city in their grip.
The incident was the third such assault against troops of the US-British coalition since their invasion on March 20 and followed the assassination of pro-Western Shiite leader Abdul Majid al-Khoei in the holy city of Najaf in central Iraq.
The fate of Saddam himself remained as much a mystery as ever, with still no evidence as to whether he was killed in a massive bombing on Monday that targeted him and his two sons.
But US Secretary of State Colin Powell said whether Saddam was alive or dead was immaterial.
"Where he is as an individual I don't know, but it really doesn't make any difference any more. The regime has been brought down and the Iraqi people are now facing a brighter future," Powell told Indonesia's Metro TV.
A tip that Saddam was hiding in a Baghdad mosque led to a fierce firefight between marines and Saddam loyalists on Thursday.