"We deny the report ... we have no information whatsoever that would indicate that the French soldiers were killed by Nato planes."
France's Le Monde newspaper on Wednesday quoted French soldiers who had survived the ambush earlier in the week near Kabul, saying they were hit in a "friendly fire" incident.
The soldiers told the newspaper they waited for four hours for backup after being ambushed.
When Nato aircraft finally arrived, they hit French troops after missing their target, the newspaper quoted the soldiers as saying.
Charges denied
Bryan Whitman, a Pentagon spokesman, on Wednesday said: "We have no reports of any casualties caused by close air support."
Asked whether French soldiers had been killed or wounded by friendly fire, he said there were "no reports of that".
Romero, a Nato spokeswoman, on Thursday said: "None of the wounds sustained by those killed or wounded were consistent with air delivery ordnance".
"No French soldier, at any time during the incident, came on the radio to say that they were taking friendly fire and no French soldier after the event has mentioned to the chain of command that this might have been the case," she said.
Herve Morin, France's defence minister, on Thursday also denied the soldiers had to wait four hours for backup.
"Fifteen to 20 minutes after the engagement of our forces, a support section left the base camp and took around 40 to 50 minutes to get to the scene," he told French radio station RTL.
'No regrets'
The comments came a day after Nicolas Sarkozy, the French president, visited survivors of the incident - the deadliest attack on French troops in 25 years - at a military base on the outskirts of Kabul.
Speaking from Kabul, where he met Hamid Karzai, Afghanistan' president, Sarkozy said he had no regrets about sending 700 reinforcements to the French contingent, adding: "If it had to be done again, I would do it.
"This is where the fight against terrorism is being waged."
Sarkozy's decision in April, after heavy pressure from Nato allies, to send an extra 700 French troops to Afghanistan, to bring their number to about 3,000, was
hugely unpopular in his country.
Opinion polls showed a large majority of French opposed the move, with many fearing that France would get bogged down in an unending war whose aims were unclear or unattainable.
About 70,000 international troops are fighting alongside Afghan security forces against Taliban fighters whose government was removed in a US-led invasion in 2001.