Some stand at mosque gates, warily cradling AK-47 assault rifles while their comrades frisk the faithful filing in to noon prayers. Others join US soldiers in the hunt for remnants of Saddam Hussein's regime. Still more are hidden in the Iraqi countryside, awaiting orders.
Some are in uniform; some wear civilian clothes. Some carry their guns openly; others have cached their weapons against the day when they might need them. Some support the US; some violently oppose it.
But all of these men are loyal to one of the various militia groups in Iraq that could pose serious threats to American plans for a peaceful transition to democratic rule. "If the Americans don't impose their authority on the people, militia groups will spring up, and there will be a lot of trouble," warns Khasro Jaaf, head of the Kurdish Democratic Party (KDP) Baghdad office. "They will grow up around the political parties here."
Organized armed groups come in many shapes and sizes in Iraq, and they have no trouble finding guns. This country has been awash with weaponry for many years - former President Hussein armed loyal tribesmen, fedayeen militiamen, and other supporters - and the collapse of the last government left military armories open to looters.
On the Baghdad black market today the most casual potential customer can find a Chinese-made AK-47 for around $25 (a Russian model costs double that) and 200 rounds of ammunition for a dollar.
The most official of the unofficial armed groups currently operating in Iraq - and the most sympathetic to the US - is the armed wing of the Iraqi National Congress (INC), the US-backed former opposition group led by Ahmed Chalabi that spearheaded exile efforts to topple Hussein.
Known as the Free Iraqi Forces (FIF), dressed in camouflage uniforms and traveling in pickup trucks draped with the same fluorescent orange flags that identify coalition military vehicles, the militiamen take orders from US Central Command, according to Zaab Sethna, the INC spokesman here. Around 1,800 of them work alongside US troops in several cities around Iraq, tracking down remaining Baath Party fighters, guarding supply depots and assuring law and order.
US officials have said they see the FIF as the potential nucleus of a reformed Iraqi army. "We are not currently recruiting because we don't have the resources and logistical facilities to handle new recruits," says Mr. Sethna. "But we are overwhelmed with applications, and we could put together a force of 15,000 men within 45 days."
Operating independently of the American forces, and increasingly hostile to them, to judge by the words of their leaders, are the Shiite Muslim armed groups that have sprung up in Baghdad and throughout southern Iraq over the past two weeks.
They say they take their orders from religious leaders based in the holy city of Najaf, and their prime task so far has been to impose law and order, since no central government authority yet exists. In the predominantly Shiite northeastern district of Baghdad, for example, hundreds of armed men, mostly in civilian clothes, guarded worshipers at an outdoor noon prayer session last Friday. They claimed to be the tip of an iceberg some 5,000 to 6,000 strong in their part of the city.
Better trained and established is the Badr Brigade, an Iranian-backed Shiite force estimated at 10,000 men, of whom some 2,000 are thought to be in Iraq now. They attacked Iraqi forces from the rear in the south of the country during the war, although they do not appear to have coordinated their operations with the coalition.
The Badr Brigade owes its loyalty to Ayatollah Muhammad Baqr al-Hakim, head of the Tehran-based Supreme Council for an Islamic Revolution in Iraq (SCIRI). He has so far boycotted US-organized meetings of former opposition groups, voicing suspicion of American intentions in Iraq, and the Badr Brigade constitutes a potentially dangerous thorn in Washington's side.
In northern Iraq, more than 30,000 Kurdish guerrillas, known as pesh merga, constitute the largest armed group in the country. They broke out of the autonomous Kurdish zone, with the assistance of US troops, to capture Kirkuk and Mosul, but have since returned to their bases, leaving Kurdish policemen - along with US soldiers - to control those cities.
Near the Iranian border, an unknown number of Mujahideen Khalq - dissident Iranians armed and trained by Hussein's regime - remain in hiding. They claim 5,000 men under arms, and were among the most vicious of the forces that Hussein used to put down the uprising that broke out in 1991 in the wake of the Gulf War.
An undetermined number of fedayeen also escaped US forces in the recent war, and are regrouping in the Diyala governorate northeast of Baghdad, along with some senior figures in the last regime, according to INC sources.
The range and number of militias could turn Iraqi politics ugly, as different political parties and ethnic groups struggle to make their presence felt. "The US talks of the disarmament of Iraq and that extends to Iraqis," says Sethna. "There cannot be armed groups outside the control of government authority, and the idea is to dismantle organized forces with command structures and funding."
In Baghdad Thursday, the retired American general appointed to spearhead reconstruction, Jay Garner, warned pretenders to Iraqi leadership that a democratic process would begin next week.
General Garner also added distance between Bush administration rebuilding efforts and Mr. Chalabi, a returned exile with little popular support in Iraq, but who is close to US defense chiefs Donald Rumsfeld and Paul Wolfowitz, and Vice President Dick Cheney. Garner said there were several leaders who are emerging, though Mr. Chalabi has enjoyed logistics support and protection from the US military. "Mr. Chalabi is a fine man, but he's not my candidate, and he's not the candidate of the coalition," Garner said.
Influence in Iraq's nascent political process from outside neighbors - especially Iran and Syria - will not be tolerated, Garner said. Still, Garner's deputy, British general Tim Cross, did not rule out a large role for the majority Shiite Muslims, if that is what a democratic process brings.
The new kingmakers of Iraq gave little detail about how they intend to jump start representative rule in a country that has known only dictatorship for 35 years. And Garner said the level of anti-American sentiment on the streets - especially among Shiite Muslims - is of a "little more magnitude than I expected."
Some former fighters hope they will not need to take up arms again, now that Hussein is out of power. "If there is nobody to battle against, why fight?" asked Sertib Hussein Shera, a Kurdish guerrilla, in between efforts to recover his family home in Kirkuk on Thursday. "No Iraqi citizen wants any more war."
But the Kurds, at any rate, are keeping their options open. As he contemplates a future operation to confiscate weapons from ordinary citizens in Kirkuk, police chief Gen. Fireyal Jawmar says he cannot promise that the pesh merga farther North will hand over their weapons. "When the new government is established, we will decide whether to cooperate and what to do."
*• Scott Peterson in Baghdad contributed to this report.