Also Tuesday, two Italian women and an Iraqi man and woman working for aid agencies in Iraq were kidnapped by gunmen in broad daylight in a busy commercial area of central Baghdad.
Witnesses said about 20 men with AK-47 rifles and pistols with silencers entered a building housing the humanitarian organization Bridge to Baghdad, according to Reuters. They left with Italian staffers Simona Pari and Simona Torretta and an Iraqi man, all employed by Bridge to Baghdad, and an Iraqi woman who worked for another Italian organization, Intersos.
"It appeared it was totally professional. It appeared they knew exactly who they wanted to abduct," said one witness who declined to be named, Reuters reported.
Bridge to Baghdad is involved in boosting school attendance in Basra and Baghdad, including Sadr City, home to thousands of Shiites.
The Italian Embassy said it had no immediate information about the abductions.
More than 100 foreigners and Iraqis have been kidnapped in Iraq since April, mostly outside the capital Baghdad. Although most have been released, the captors have killed several foreigners in recent months.
Insurgents kidnapped and killed Italian journalist Enzo Baldoni in August. In April, kidnappers killed Italian security guard Fabrizio Quattrocchi. The fate of two French journalists is still in the hands of an Islamic militant group.
The fighting in Sadr City erupted when militants attacked U.S. forces on patrol, killing an American, said U.S. Army Capt. Brian O'Malley.
An al-Sadr spokesman in Baghdad, Sheik Raed al-Kadhimi, blamed what he called intrusive American incursions into Sadr City and attempts to arrest the cleric's followers.
"Our fighters have no choice but to return fire and to face the U.S. forces and helicopters pounding our houses," he said in a statement.
Peace talks in Sadr City between al-Sadr's representatives and interim Prime Minister Iyad Allawi's government have stalled over the government refusal to remove U.S. troops from the area.
The violence came a day after a car bomb blew up next to a U.S.-Iraqi military convoy near the Sunni Muslim insurgent stronghold of Fallujah, west of Baghdad, killing seven U.S. Marines and three Iraqi soldiers.
The force of the blast destroyed two Humvees and hurled the suicide car's engine far from the site, according to the AP.
The Defense Department Web site says 990 U.S. troops, including three civilians, have been killed in Iraq since the March 19, 2003, start of the war.