Guerrillas and U.S. troops battled for hours here on Friday in an intense firefight after a demonstration in support of Saddam Hussein turned violent.
In Baghdad, rumors of terrorist attacks this weekend roiled the city.
The daylong battle in Abu Ghraib, a western suburb of Baghdad that has been a center of hostility to the U.S.-led occupation, and the anxiety in the capital underscored the deteriorating security situation here at the end of a week that began when four simultaneous car bombs killed 34 people and wounded more than 200.
In addition, a U.S. soldier was killed on Friday in an attack west of Baghdad. At least 33 U.S. troops have died from hostile fire in October, compared with 16 in September, and the pace has increased in recent days.
The soldier, from the 82nd Airborne Division, was killed by a roadside bomb at 8:30 a.m. near Khaldiya, about 45 miles west of Baghdad, the military reported. Four other soldiers were wounded.
The death brought to 118 the number of U.S. troops killed in action since President Bush declared major combat operations over on May 1. Since the Iraq war began on March 19, 350 soldiers have died in combat or from other causes, and 2,160 more have been wounded, said Maj. Linda Haseloff, a military spokeswoman in Tampa.
This weekend could see a surge in terrorist or guerrilla attacks, the New York Times reported. Administration officials in Washington said fliers circulating in Baghdad and Basra urged a three-day general strike against the occupation.
Schools, hotels and several neighborhoods have received specific threats, according to the military and local residents, and there is talk that hundreds of Islamic militants have infiltrated the capital.
Around Baghdad, Iraqi police officers set up checkpoints at major intersections to look for weapons. Private security companies, hired by the big hotels where foreign journalists and contractors are staying, dispatched teams of bomb-sniffing dogs to examine cars parked nearby.
In Abu Ghraib, about 10 miles west of Baghdad, helicopters rattled overhead and U.S. soldiers moved M1 Abrams tanks into the area to counter Iraqi guerrillas. The hollow thump of mortar rounds from guerrillas sounded near a market where U.S. soldiers are attacked regularly.
Some U.S. troops fired from combat vehicles while others on foot took up fighting positions in the area, soldiers said. Iraqis said there were civilian casualties, but the report could not be confirmed. A military spokesman in Baghdad declined to comment on the battle.
Local residents and U.S. soldiers offered different accounts of the genesis of the firefight. Residents said the violence grew out of an effort in the morning by U.S. soldiers and Iraqi police officers to clear vegetable sellers from the street. Soldiers threw a stun grenade into the crowd, injuring some Iraqis, they said. After Friday prayers, a pro-Hussein demonstration of at least 1,000 people gathered, intensifying the confrontation, the residents said.
"People started calling, "By blood and soul we sacrifice for you, Saddam Hussein,' " said one witness, Hamad Ali. Then the Iraqi police fired on the demonstrators, and a firefight broke out, Ali said.
But U.S. soldiers said the violence flared when someone threw a grenade at troops patrolling the market, slightly wounding two soldiers. Then the police station was hit by mortars, they said. On Sunday night, a mortar attack on the station killed at least one person and wounded two others.