A general staff statement said images from unmanned surveillance aircraft, leaked to the media earlier this month, showed the rebels after they had launched the attack on a unit at the Iraqi border and not before as alleged.

The Taraf daily, which routinely targets the army, had claimed commanders failed to take action despite seeing the approach of the rebels in live images captured by the drones and did not send reinforcement to help the soldiers.

It was the latest in a series of allegations targeting the Turkish army, already under unprecedented pressure over several court cases against dozens of acting and retired soldiers accused of involvement in alleged plots to discredit and topple the Islamist-rooted government.

"The images seen in the media belong to the process after fighting erupted," the army statement said, adding that commanders "took or tried to take the necessary measures."

An internal army probe established that fog and a dust storm delayed by about three hours the arrival of helicopter gunships sent as reinforcement to the area, it said.

Six soldiers were killed when rebels of the separatist Kurdsitan Workers' Party assaulted a military unit near the border town of Cukurca on July 20, in one of their bloodiest attacks this year.

The military has said at least nine PKK militants were killed in the fighting.