Insurgents unleashed a pair of powerful car bombs Monday near the symbol of U.S. authority in Iraq — the Green Zone (search), where the U.S. Embassy and key government offices are located — and hotels occupied by hundreds of foreigners. Two other explosions brought the day's bombing toll to at least 24 dead and more than 100 wounded.

More than three dozen car bombings since the beginning of September illustrate the militants' seeming ability to strike at will despite recent pledges by the United States and Iraq to intensify the suppression of insurgents, and the morale-boosting recapture of Samarra over the weekend.

Defense Secretary Donald H. Rumsfeld (search) said Monday he does not expect a civil war to erupt in Iraq, and pointed to the formerly insurgent-held city of Samarra (search) as an example of success.

"I don't think it's going to happen," Rumsfeld said in New York at the Council on Foreign Relations, when asked about the threat of civil war. "But what has to be done in that country is what basically was done in Samarra over the last 48 hours."

The day's violence also included assassinations of three Iraqis, and U.S. attacks against targets in insurgent-held Fallujah. In the latest hostage developments, kidnappers freed two Indonesian women, but a separate militant group claimed to have killed a Turkish man and a longtime Iraqi resident of Italy.

No coalition forces were wounded in either of Monday's blasts in Baghdad, said Maj. Phil Smith, a spokesman for the 1st Cavalry Division. But the U.S. command reported two of its soldiers were killed at a Baghdad traffic checkpoint Sunday.

In the first car bombing Monday, insurgents detonated a four-wheel drive vehicle packed with explosives at the western entrance of the heavily fortified Green Zone about 8:45 a.m., said Interior Ministry spokesman Col. Adnan Abdul-Rahman.

"I was thrown 10 yards away and hit the wall," said Wissam Mohammed, 30, who was visiting a nearby recruiting center for Iraqi security forces. His right hand broken, his head wrapped in bandages and his clothes stained with blood, Mohammed lay in a bed at Yarmouk Hospital.

The hospital took in 15 bodies and 81 wounded from the explosion, said Sabah Aboud, the facility's chief registration official.

An hour later, across the Tigris River, a pickup truck packed with dates and explosives plowed into a three-vehicle convoy as it left a parking lot shared by several high-rise hotels housing hundreds of foreign contractors and journalists.

As people rushed to help, gunmen began shooting from the rooftops and police returned fire, said Tahsin al-Kaabi of the Facility Protection Service, a U.S.-trained civilian guard force.

At least six people were killed and 15 wounded, said Tahsin al-Freiji, another guard force member.

One of the four-wheel drive vehicles was destroyed and the pickup truck carrying the explosives was ripped in half, with one part left dangling from a shop sign on the opposite side of the street.

At least five other cars were charred, including one of the targeted vehicles, which had a burned body in the front passenger seat. A head and other body parts were strewn in the road amid shards of glass.

"I was on my way to work. We heard a big boom and I briefly passed out," said Razaq Hadi, 36, who was in a minibus that was damaged by the blast. "I saw seven of the passengers who were seriously wounded being taken out through the broken windows."

The driver was killed. "I saw his body torn apart," said Hadi, who was covered in the man's blood.

Both the Green Zone and the area around the hotels have been targets of previous attacks that have killed dozens of people.

Last month saw at least 39 car bomb attacks in Iraq — the highest number in any month since the U.S.-led invasion in March 2003. On Sept. 30, insurgents set off a series of vehicle explosives that killed at least 35 children and seven adults at a government ceremony in Baghdad.

Two more car bombs exploded Monday in Mosul, 225 miles northwest of Baghdad.

One of the blasts killed a civilian bystander and two people believed to be transporting explosives, said Capt. Angela Bowman, a military spokeswoman. Hospital officials said they treated 11 wounded. The second bomb targeted a U.S. Army convoy, wounding one American soldier, Bowman said.

In Baqouba, a city 35 miles northeast of the capital, a police commander was assassinated in a drive-by shooting, police said. Insurgents also fired mortar rounds at a municipal building, killing one person and wounding seven.

There were also assassinations in Baghdad, where gunmen killed a senior official of Iraq's Sciences and Technology Ministry and a female employee near the southeastern Zayona suburb, Abdul-Rahman said.

Monday's violence came despite promises by U.S. and Iraqi officials to crack down on insurgents ahead of elections slated for January and wrest key parts of the country from their control.

Late Monday, U.S. warplanes attacked the sprawling Baghdad slum of Sadr City (search), and skirmishes were continuing between American troops and rebels in the area, a spokesman for the insurgents said. The U.S. military had no information on the reported fighting, but American forces have staged almost daily attacks there in an effort to root out militiamen loyal to radical Muslim cleric Muqtada al-Sadr.

In Fallujah (search), American warplanes unleashed strikes against suspected terrorist hideouts and weapons caches early Monday. At least 11 people, including three women and four children, died in the attacks and 12 others were wounded, hospital officials said.

The military, which regularly accuses hospitals of inflating casualty figures, said the strikes targeted followers of Jordanian terrorist Abu Musab al-Zarqawi.

It was the latest in weeks of strikes in the city 40 miles west of Baghdad aimed at groups with links to terrorists, particularly al-Zarqawi's network. Followers of the Jordanian militant have claimed responsibility for a string of deadly bombings, kidnappings and other attacks across the country.

In Samarra, 60 miles northwest of Baghdad, U.S. troops patrolled in tanks, armored personnel carriers and Humvees as sporadic gunfire broke the relative calm Monday. U.S. soldiers, accompanied by Iraqi translators carrying lists, entered houses asking about specific people.

Iraqi National Guard forces have captured 40 foreign fighters, including Egyptians, Sudanese and a Tunisian, since entering Samarra early Friday, Defense Minister Hazem Shaalan told Arab TV network Al-Arabiya.