The release of two French journalists kidnapped in Iraq was delayed on Friday because of US firing at Iraqis transporting the hostages, said French lawmaker Didier Julia involved in negotiations to free the hostages.

Julia told a news conference here that his assistant Philippe Brett had persuaded the kidnapppers to release the two French journalists, Christian Chesnot, 37, and Georges Malbrunot, 41, and they had left in two separate convoys from their place of detention, both of which had come under US fire.

"They set up 20 roadblocks and ... six members of the team protecting the journalists were killed," said Julia, adding Brett had learnt of the failure of the mission as soon as he arrived separately at the Syrian border and headed straight back to the journalists' captors.

Philippe Evanno, an aide to Julia, also confirmed that a convoy bringing the hostages to Syria came under US fire, scuttling their release.

He added that six Iraqi kidnappers were killed during the alleged US attack, but the two hostages were unharmed. The two French journalists were no longer in the hands of the Islamist militant group that took them hostage on Aug. 20 but with another "Iraqi resistance group" that sought to free them, Evanno said.

However, US forces in Iraq said they had no reports to indicate there was any truth to the allegation by the French lawmaker.The two French journalists disappeared on Aug. 20 with their Syrian driver while apparently driving toward Iraqi city of Najaf.Later, a militant group calling itself the Islamic Army in Iraq claimed responsibility for kidnapping the two French journalists, demanding France to revoke a new law banning Islamic head scarves from state schools.