France's worst single military loss in a quarter-century, which is expected to shake public confidence - though not President Nicolas Sarkozy's resolve in the war on terror - may have been caused by friendly fire, according to a report published Wednesday.

The North Atlantic Treaty Organization said it will look into a media report alleging that the French soldiers, after being ambushed by insurgents, faced fire by aircraft and Afghan soldiers sent to rescue them, according to Agence France-Presse. "We are aware of the media reports and therefore we have to look into it," an unidentified official told AFP, referring to interviews with soldiers in the newspaper Le Monde.

Ten French paratroopers were killed and 21 wounded in the worst single battlefield defeat for the allies since the Taliban regime was ousted in 2001. It was France's biggest loss since a truck bomb killed 58 French soldiers in Beirut in 1983.

"I came to tell you that the work that you are doing here is essential," Sarkozy told French troops after flying to Kabul Wednesday.

"The best way to be loyal to your comrades is to continue your work, is to raise your head, to be professional."

Some of the wounded soldiers were to arrive here Wednesday evening, as well as the bodies of those killed. A ceremony in Paris Thursday will draw citizens and officials together to honour the dead.

The tragedy dominated newspaper front pages and many private conversations.

"It's tragic, and I'm very sad what happened to those young boys," said Martine Roussel, a woman in her 50s who lives in a Paris suburb.

"I don't think our troops should be there," she told Canwest News Service.

"The Taliban are gaining ground little by little."

Businessman Daniel Bednar, a Canadian from Vancouver who has worked and lived in Paris for 18 years, said the loss is a huge shock for the French even though the country's total casualties in Afghanistan are far lower than Canada's.

He said his own mixed feelings about France's 3,000-plus troop commitment to Afghanistan are turning negative as a result of Monday's tragedy.

He said problems relating to Muslim terrorism in Europe and in former French colonies in North Africa appear more relevant to France.

That concern was mirrored in a Le Monde editorial Wednesday which said Sarkozy "must explain to French people why their soldiers are dying 6,000 kilometres from their territory."

The left-wing Liberation newspaper's editorial called the conflict an "unwinnable" war, though it clashed with leading left-wing politicians who oppose France's involvement.

"The worst solution would obviously be withdrawal," concluded the editorial, which described the overthrow of the Taliban after the 2001 terror attacks in New York and Washington a "tragic necessity."

One German analyst dismissed any suggestion that the incident, which showed that the Taliban is capable of more than just planting roadside bombs and assassinating unarmed civilians, will weaken Europe's commitment to the military.

The French and German motive for being in Afghanistan is "to improve the bilateral relations with the U.S., including redefining the French role in NATO (Sarkozy) or to prove how reliable its German ally is," Citha Maass, an analyst with the German Institute for International and Security Affairs, told Canwest in an e-mail.

American analyst John Glenn, of the German Marshall Fund policy think-tank, said his organization's still-unpublished polling has indicated surprisingly "robust" French support for the Afghanistan mission.

He predicted that the U.S. and its NATO allies will seriously consider a troop surge after the U.S. election in order to crush Taliban momentum.

Jerome Foucquet, of the polling firm Iftop, said an April poll showed that 55 per cent of the 1,004 surveyed were opposed to Sarkozy's decision to increase France's troop commitment in Afghanistan by 700, compared to 45 per cent in favour.

He said Monday's deaths will likely boost the number of opponents.

The poll had an error margin of between two and three percentage points, he said.