In other violence a week after Iraq's election, two Iraqi National Guard soldiers were killed and three more were injured Sunday in an attack on a patrol in central Iraq, the Polish military said.
Two rockets exploded on the edge of the Baghdad International Airport compound, raising a large plume of smoke above the city skyline. A third rocket slammed into an Iraqi National Guard building in a western suburb but there was no report of casualties.
Attackers gunned down an Iraqi contractor who apparently worked with the U.S. military, and police in Karbala reported that a suicide car bomber struck a U.S. convoy south of the city Sunday morning, destroying an American vehicle.
The U.S. military had no information on the blast, and there was no word on casualties.
In other developments:
The four kidnapped Egyptians were seized early Sunday near the Mansour district of western Baghdad, the official said on condition of anonymity. They worked for Iraqna, a subsidiary of the Egyptian firm Orascom Telecommunications, which operates the mobile phone network in Baghdad and central Iraq.
Six other Egyptians working for Iraqna were kidnapped in two separate incidents in September. All were ultimately freed although Orascom said at the time that it was committed to continuing its work in Iraq.
The Italian journalist was kidnapped Friday by gunmen who blocked her car outside Baghdad University. Giuliana Sgrena, 56, is a veteran reporter for the left-wing daily Il Manifesto.
A statement Saturday on an Internet bulletin board used by extremist groups said she would be subjected to the "rule of God," a phrase that usually means punishment by death in the lexicon of Islamic militant groups.
The new Web message was signed by the Jihad Organization. It was unclear whether the group was the same as one that posted an Internet statement hours after the abduction on Friday.
In that message, a group calling itself the Islamic Jihad Organization claimed to have kidnapped the woman and gave Italy 72 hours to withdraw its troops. But it made no threats to kill her or say what would happen if its demands were not met.
Neither statement included a picture of the woman or other evidence to support the claims.
A top Foreign Ministry official in Rome said Italy was investigating whether the journalist was seized by insurgents or by ordinary criminals hoping for a ransom.
Italian officials have also publicized her pacifist convictions in hopes it might help win her release.
Italy has about 3,000 troops in Iraq, one of the largest coalition contingents after those of the United States and Britain.
The two Iraqi guardsmen were killed in an ambush in Babil province, a mixed Shiite-Sunni area which had been a flashpoint of rebel activity. Three other Iraqi guardsmen were injured, the Polish military command in the area said.
Also Sunday, an Iraqi civilian was wounded by a roadside bomb that exploded but missed an Iraqi police patrol in the southern port city of Basra, police said.
Elsewhere in the city, gunmen fired rifle shots at a gasoline tanker truck, and the vehicle exploded into a huge ball of fire. No one was hurt, said police Capt. Mushtaq Talib.
The tanker was heading to an illegal port used by oil smugglers in the city, Talib said.
In another attack, gunmen fired on a group of Iraqi policemen working to dismantle a roadside bomb on a main street in central Baghdad, injuring two officers, a police official said.