US-led troops continued to engage in sporadic battles against rebels in Fallujah after launching a major assault to wrest the Sunni Muslim city west of Baghdad from insurgents 10 days ago.
The military shelled the southern outskirts of the city, an AFP photographer said, even after a US marine officer had declared on Wednesday that "the battle is over".
Iraqi volunteers and US troops were able to clear 24 corpses from the battered city and evacuate five civilians, an AFP correspondent said.
The Iraqi Red Crescent said 150 families remained stranded.
Iraqi police and national guards detained more than 100 suspected militants in raids around Haifa Street, a rebellious Sunni stronghold in Baghdad, an Interior Ministry spokesman said.
In all 104 people were arrested, including nine who were suspected of having escaped from the US-led offensive against the rebel city of Fallujah over the past 10 days, spokesman Sabah Kadhim said. Many weapons were also seized, he added.
"They are mainly Iraqis but there may be some Syrians and other Arabs," Kadhim said.
US troops were involved in backing up the raids, in an area where they have clashed with anti-American insurgents in recent months. Militants in Haifa Street and Fallujah have been blamed by the Iraqi government for bomb attacks in the capital.
The US marine intelligence report warned that any significant troop withdrawal from Fallujah would strengthen the insurgency, The New York Times said.
The assessment, distributed to senior marine and army officers in Iraq, said that despite the heavy fighting, the insurgents would continue to increase in number, carrying out attacks and fomenting unrest.
"The enemy will be able to effectively defeat (the marines') ability to accomplish its primary objectives of developing an effective Iraqi security force and setting the conditions for successful Iraqi elections."
Military officials in Iraq and Washington disputed the report's findings, saying they represented only the "worst-case assessment" and that there would be no pullout of US troops from the city.
The assault on Fallujah, part of a bid to reclaim key rebel enclaves across the country ahead of January elections, has been the largest military operation in Iraq since the March 2003 invasion.
Despite attempts to bring the insurgency to heel before the polls, a statement posted on the website of a militant group Ansar al-Sunna on Thursday threatened to attack both candidates and voters in elections.
"We will target anyone who dares to stand in these elections because they will be considered apostates," said the statement, whose authenticity could not be independently verified.
As fighting winds down in Fallujah, Iraqi commandos backed by US troops were set to storm rebel strongholds in the main northern city of Mosul, where US-led forces are trying to clear insurgents who overran police stations last week.
Five Iraqi soldiers were wounded in a mortar attack in the west of the city, Lieutenant Ziad Framzi said.
The operations came as more deadly violence shook Iraq a day after at least 23 people were killed in unrest across the Sunni belt.
At least 17 Iraqis died in attacks around the country, including a suicide car bombing in Baghdad and roadside bombings north of the capital, police said.
Meanwhile, the United States became the latest nation to condemn the apparent murder of Margaret Hassan, the head of CARE International's Iraq operations who was seized by unknown attackers on October 19 while on her way to work.
"We strongly condemn the abduction and murder of this prominent humanitarian," White House spokesman Scott McClellan said in a statement. "Her death is a great loss to the Iraqi people and the world."
If her death is confirmed, she would be the first foreign female hostage known to have been murdered in Iraq, and the second British hostage.
Australian Prime Minister John Howard backed away from an earlier statement in parliament that the mutilated body of a woman found in Fallujah appeared to be that of Hassan.
He did say there was every indication that Hassan was the woman who appeared in a video received by Al-Jazeera Tuesday showing an armed man shooting a blindfolded woman in the head.
The body of a blonde woman with her legs and arms cut off and throat slit was found Sunday lying on a street in Fallujah. It has not been identified.
Meanwhile, Prime Minister Iyad Allawi voiced his concern to the US military after footage of a US marine killing a wounded Iraqi in a Fallujah mosque was broadcast world-wide.
The incident shocked Arab television audiences and the pictures dealt a fresh blow to the image of the US-led forces in Iraq. The marines said the man involved had been withdrawn from the battlefield pending the results of an investigation.
And differences between world powers over Iraq again moved into the spotlight at an Anglo-French summit.
French President Jacques Chirac arrived in Britain, with Iraq a sore point after the man who led European opposition to the US-led war said he was not convinced that the world had become safer since the downfall of Saddam Hussein.
"There's no doubt that there has been an increase in terrorism and one of the origins of that has been the situation in Iraq. I am not at all sure that one can say that the world is safer," said Chirac.
But Britain and France both want a "stable and democratic Iraq" despite their falling out over the war, British Prime Minister Tony Blair said after his talks with Chirac.
Iraq was also likely to emerge as a key issue at this weekend's Asia-Pacific Economic Co-operation (APEC) forum in Chile where US President George W. Bush, on his first trip abroad since winning re-election, will seek support for his policies.