Insurgents battled American troops in the streets of Baghdad on Saturday, killing a U.S. soldier in an ambush and gunning down four government employees in signals that the guerrillas remain a potent force despite the fall of their stronghold of Fallujah (search). Nine Iraqis also died in fighting west of the capital.

In Fallujah, where U.S. Marines and soldiers are still battling pockets of resistance, insurgents waved a white flag of surrender before opening fire on U.S. troops and causing casualties, Marine spokesman 1st Lt. Lyle Gilbert said Saturday without elaborating.

Al-Arabiya television quoted Iraqi guerrillas fleeing Fallujah as saying they had run out of ammunition and many fighters who stayed behind were badly wounded.

U.S. troops in the northern city of Mosul (search) found the bodies of nine Iraqi soldiers Saturday, all shot in the back of the head. The military first reported that seven of the victims were beheaded, but a second statement issued later Saturday said those reports were false.

Four decapitated bodies found earlier in the week in Mosul have not been identified, the military said Saturday. American and Iraqi forces detained 30 suspected guerrillas overnight in Mosul, the U.S. military said.

In a positive development, a Polish woman abducted last month in Baghdad reappeared Saturday in Poland after being suddenly released. Teresa Borcz Khalifa (search), 54, refused to say how she was freed but said her captors treated her "properly" — treatment that they told her was "motivated by their religious beliefs."

But the widespread clashes in Baghdad — which broke out early Saturday in at least a half-dozen areas — and other areas of central and northern Iraq underscored the perilous state of security in this country after 18 months of American military occupation — and just more than two months before vital national elections.

One American soldier was killed and nine were wounded in an ambush in central Baghdad. Five other U.S. soldiers were injured in a car bombing on the road to Baghdad's airport — considered by U.S. authorities among the most dangerous routes in the country.

A Web posting claimed responsibility for the attack in the name of a group led by Jordanian terror mastermind Abu Musab al-Zarqawi (search), who is believed to have fled Fallujah before the city fell this month to U.S. forces. The veracity of the claim could not be confirmed.

Iraqi Brig. Gen. Anwar Mohammed Amin said he had seen various reports placing al-Zarqawi in the Tuz Kharmato area south of Kirkuk and in the Baqouba area.

The heaviest fighting in the capital took place in the Azamiyah district, a largely Sunni Arab quarter, where insurgents fired rocket-propelled grenades and small weapons at a police station, killing one policeman, Iraqi officials said.

Anger among Sunnis rose after Iraqi troops backed by U.S. soldiers Friday raided the Abu Hanifa mosque in Azamiyah — one of the most revered sites in Sunni Islam. Three worshippers were killed, witnesses said.

A number of U.S. armored vehicles were seen in flames, including a U.S. Army Humvee with what appeared to be a body in the driver's seat. Smoke rose from burning shops along a commercial street as U.S. helicopters circled overhead and ambulances raced to the scene.

The U.S. command said the American soldier died when his patrol came under a coordinated attack including small-arms fire, rocket-propelled grenades and roadside bombs. The statement did not specify where the attack occurred or whether it was part of the Azamiyah fighting.

Clashes also erupted in the western Amiriyah neighborhood, long a center of insurgent activity, after three Iraqi National Guardsmen were killed by roadside bombs, policeman Akram al-Azzawi said.

A suicide driver blew up his vehicle shortly after noon at an intersection on Saadoun Street, a bustling commercial street. One Iraqi civilian was killed and another wounded in the blast, which sent black smoke rising above the city center and set several cars ablaze.

Gunmen chased down a vehicle carrying Ministry of Public Works employees on their way to work Saturday, opening fire and killing four of them, a ministry spokesman said. Amal Abdul-Hameed — an adviser to the ministry in charge of urban planning — and three employees from her office died, spokesman Jassim Mohammed Salim said.

To the west of the capital, U.S. troops clashed with insurgents Saturday near the local government building in Ramadi, and hospital officials said nine Iraqis were killed and five were wounded.

Earlier, U.S. troops sealed off roads and launched a house-to-house search of the city's Tamim neighborhood as U.S. helicopters flew overhead, playing loudspeakers urging residents to "hand over terrorists," police Lt. Jamal Abdul-Kareem said.

Elsewhere, saboteurs blew up an oil well near the northern city of Kirkuk — the sixth such attack in the last 10 days, oil officials said. Insurgents regularly attack Iraq's oil infrastructure, which provides much of the revenue for reconstruction.

Clashes occurred between U.S. troops and insurgents in Qaim along the Syrian border and in Samarra, where mortar shells struck a U.S. base but caused no casualties. Five Iraqis were hurt in the Qaim fighting, the local hospital reported.

In Baqouba, 35 miles northeast of Baghdad, police said gunmen killed an Iraqi police colonel and his driver as they headed south to Baghdad.

Violence surged in Sunni areas of central and northern Iraq after U.S. and Iraqi forces launched a major attack Nov. 8 against the main rebel stronghold of Fallujah in hopes of restoring order so national elections can be held by Jan. 31.

But many militants are believed to have fled the city to continue attacks elsewhere — and the operation risks alienating Iraq's Sunni Arab minority, whose participation in elections is seen as key to legitimacy.

Al-Zarqawi's group, which recently declared its allegiance to al-Qaida, is believed responsible for numerous car bombings and beheadings of foreign hostages, including three Americans. The United States has placed a $25 million bounty on al-Zarqawi — the same amount as for Osama bin Laden.

In New York, Iraq's ambassador to the United Nations said his government has "a good chance" of being able to hold the elections in January but might have to postpone them if violence escalates or Sunni Muslims decide to boycott.

Ambassador Samir Sumaidaie told a news conference Friday that "what happens in the next weeks will be important" in determining whether the insurgents can rally after losing their Fallujah base.

In an effort to shore up the government, Germany and the United States announced agreement on a deal forgiving 80 percent of Iraq's foreign debt. The deal will be discussed by the Paris Club of creditor nations, which is owed about $42 billion by Iraq.

The United States has been pushing for a generous write-off of as much as 95 percent of Iraq's debt. However, other governments, including Germany, have questioned whether a country rich in oil should benefit from huge debt reduction.