The Frenchmen have been shown in a video pleading for their release

But Sunni Muslim clerics in Iraq say efforts to free them are being hampered by the escalation of security operations led by US forces.

Australia is investigating whether a body found north of Baghdad is that of one of its citizens.

There has been no news on the fate of a Briton and two US nationals abducted from a house in Baghdad on Thursday.

The three were seized at gunpoint by a gang who raided the house in the capital's Mansour neighbourhood.

The US embassy in Iraq named the two Americans as Jack Hensley and Eugene Armstrong.

The British embassy did not release details of the Briton but Foreign Secretary Jack Straw has contacted the man's family to reassure them the UK is doing everything it can for him, his department said on Friday.

'Alive and well'

French Defence Minister Michele Alliot-Marie said she had new information on the fate of journalists Christian Chesnot and Georges Malbrunot, who disappeared in Iraq nearly a month ago.

KIDNAP FACTS More than 100 foreigners seized (including two Italian aid workers, pictured) 19 being held 25 killed, including (12 Nepalese) At least 3 Americans seized: Nick Berg - civilian - beheaded; Keith Maupin - soldier - killed (unconfirmed); Thomas Hamill -civilian - escaped One Briton kidnapped: James Brandon - journalist - released Hostage facts Iraq's hostage-takers

"We have information that allows us to think - without having direct proof - that our hostages are alive, safe and in good health," she told Le Parisien newspaper.

"All the relevant ministries, including defence, of course, are permanently mobilised," she added.

The Committee of the Ulema, Iraq's top Sunni religious organisation also suggested the pair were still alive but said attempts to free them were being frustrated.

"We are under the impression that the American forces do not want the hostages to be freed because each time we get near a solution, these forces push for a military escalation," said Mohammed Ayash al-Kubaisi, the group's representative abroad.

"We believe these forces have political aims, seeking to create a chaotic situation which does not contribute to progress," he told AFP news agency in Qatar.

Body found

Early on Friday, the body of a man said to have western features was pulled from the River Tigris near the central Iraqi village of Yethrib.

A spokesman for Australia's foreign minister said they were trying to determine if the victim was one of two Australian security guards whom militants claim to have taken hostage.

The latest kidnappings bring the number currently being held to 19.

Two female Italian aid workers were taken last week.