The chaos has fanned sectarian tension and deepened Sunni distrust of interim Prime Minister Ayad Allawi, a Shiite installed by the Americans five months ago. It has also heightened the anxiety of the city's 6 million people - already worn down by years of sanctions and tyranny, then war, military occupation, crime and deprivation.
''Baghdad is now a battlefield and we are in the middle of it,'' said Qasim al-Sabti, an artist who kept his children home from school Saturday, which is a work day in Iraq. When he sent his children back to school Sunday, the teachers didn't show up.
After sundown Sunday, four large explosions shook the area near Baghdad's U.S.-guarded Green Zone - a frequent target of insurgent mortars and rockets. There was no word on any damage or casualties.
In a sign of public unease, merchants in the outdoor markets, where most people buy their meat, vegetables and household supplies, say crowds are below normal. Many shops near sites of car bombings have closed.
Adding to the sense of unease, U.S. military helicopters have begun flying lower over the city. The distant roar of jets has become a fixture of Baghdad at night.
The latest escalation appeared to have been triggered by a U.S.-Iraqi raid Friday on the Abu Hanifa mosque in the Sunni neighborhood of Azamiyah as worshippers were leaving after midday prayers. Witnesses said three people were killed, and 40 were arrested.
The next day, heavy street fighting erupted in Azamiyah between U.S. and Iraqi forces and Sunni insurgents who tried to storm a police station. The fighting, involving mortars, rocket propelled grenades and roadside bombs, raged for several hours and left several stores ablaze, according to witnesses.
Almost simultaneously, clashes broke out in at least five other Baghdad neighborhoods. In all, at least 10 people, including one American soldier, were killed throughout the capital Saturday.
Lt. Col. James Hutton, spokesman for the U.S. Army's 1st Cavalry Division, which is in charge of security in Baghdad, acknowledged that there has been an increase in insurgent activity in the capital.
But he linked the increase to the fighting in Fallujah, where U.S. troops are still fighting pockets of resistance after recapturing the city last week, rather than the raid on the Abu Hanifa mosque.
The government has said the raid was carried out because of suspicions of ''terrorist activity'' there. It appears the operation was part of a crackdown on militant Sunni clerics, many of whom are believed to have links to some insurgent groups and who had spoken out against the Fallujah operation.
The Friday raid came at a time when sectarian tensions in Baghdad were already running high over the assault on the mainly Sunni Arab city of Fallujah. Baghdad's population is a potentially explosive mix of Sunnis, Shiites and Kurds. With frustration mounting over soaring crime, unemployment and poor services, Allawi can ill-afford to allow Baghdad to descend further into chaos.
The signs, however, are not encouraging. With the Jan. 30 national election now only two months away, the rivalry between various ethnic and religious groups is intensifying.
Adding to the public discontent is a fuel shortage - ironic in a country with some of the world's largest petroleum reserves. Motorists must line up for hours behind hundreds of other cars at gasoline stations throughout the city.
Iraq's oil facilities have been the frequent target of insurgent attacks.
Electricity supplies remain erratic, with frequent outages plaguing the city. Residents of some Baghdad neighborhoods complain there has been no garbage collection for weeks, leaving them no choice but to burn their trash.
A nighttime curfew imposed this month under a 60-day state of emergency empties the city shortly after sunset.
The rising tension has prompted many Baghdad parents to keep their children home from school. College students say many of their classmates never showed up for Saturday or Sunday classes. In areas hit by violence, some shops stayed shut.
''If I am meant to die, then there is nothing that I can do about it,'' said Mohammed Rafid, 18, a computer programing student at Baghdad's Mansour college and one of those who showed up for class Sunday.
Rafid, however, said nearly half of the 46 students in his class stayed home.
Tensions are likely to sharpen as the Jan. 30 election date approaches. The ballot is expected to confirm the domination of Iraq's Shiite community, estimated at 60 percent of the nearly 26 million population.
Victory would allow the Shiites to shrug off decades of oppression by the Sunni Arabs, a powerful minority that had long dominated Iraq. Most Kurds are Sunni, but they are resented by many Arab Sunnis because of their close ties to the Americans and for what are perceived as sucessionist tendencies.
Prominent Sunni clerics are calling on supporters to boycott the vote in retaliation for the fighting in Fallujah. A Sunni boycott would greatly undermine the legitimacy of the vote for a 275-member assembly, whose main task will be draft a permanent constitution for Iraq.
The conflicting interests of the Sunnis and Shiites can be seen in the graffiti, banners and posters in Sunni Azamiyah and across the Tigris River in the mainly Shiite district of Kazimiyah.
In Azamiyah, graffiti and banners praise Fallujah's insurgents as heroes and denounce the Iraqi National Guard, which some Sunnis call ''Allawi's Army'' because of the high number of Shiites in its ranks. ''Jihad (holy war) is the gift of men,'' declares one banner.
In Kazimiyah, home to one of Shiism's holiest shrines, Iraqis are urged to register to vote and to take part in the election.
''A vote is worth more than gold,'' read several banners, purportedly quoting Grand Ayatollah Ali al-Sistani, Iraq's top Shiite cleric who has pushed hard for elections since Saddam's ouster 19 months ago.
Will the January elections in Iraq be successful?
I Don't Know 15%
Total Votes: 31,746