U.S. Marines fought alongside the British military to stop an assassination attempt on Britain’s Prince Harry last September, losing two of their own servicemen and millions of dollars in U.S. military aircraft.

The third-in-line to the throne was stationed for three months at Camp Bastion, a British military base in southern Afghanistan that was generally considered an impregnable fortress. But the attack by Taliban forces dressed in U.S. Army uniforms proved that assumption wrong, GQ said in its exclusive, detailed account of events.

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Taliban forces arrived at night in three teams of five, infiltrating the miles-wide base. The first gunfire came from the area where Harrier jets were located, followed quickly by explosions that would eventually cripple six of the jets.

Initially, U.S. Marines heard the explosions and thought they were being attacked by air, the magazine said. But gunfire soon made it apparent that a ground force had invaded the camp.

Next door to the Harrier compound, Capt. John Buss and another soldier heard gunfire and upon realizing it was "inside the wire," pulled their Beretta 9 mm pistols and went to check out the situation. Seeing the group of men wearing U.S. Army uniforms, Buss told GQ that he wasn’t sure if they were friends or foes.

"Then one of the men shouldered a rocket-propelled grenade launcher and, taking aim, fired an RPG at one of the Harriers, which exploded into a massive ball of flame. Buss couldn't believe his eyes — it was like watching a movie," GQ reported

Prince Harry was secured by British soldiers in a safe area before they joined the fight, and the British government later said the royal was never in danger. After the attack was over, the Taliban said it was an assassination attempt, as well as an opportunity to destroy American aircraft, Al Jazeera said.

As the Harrier compound was destroyed, GQ said, it became clear to the Marines that they had to get firepower into the air to take control of the situation. Helicopter commander Lt. Col. Stephen Lightfoot saw the burning jets and made the call to fly over the area.

The challenge with fighting in the air was that the Taliban were dressed in Army uniforms, making it nearly impossible to tell who was the enemy. Pilot Maj. Robert Weingart was in the air, but was concerned about risking the lives of his own troops. To solve the problem, he called and asked the soldiers on the ground to all fire at once toward the intruders. Using his night vision, he traced the direction of the gunfire and sent his Cobra on attack, GQ said.

It was the turning point in a deadly attack. All but one of the 15 Taliban were killed, with the last one being captured. Killed in the attack were Lt. Col. Christopher Raible and Sgt. Bradley Atwell.

In April, the Washington Post reported U.S. military officials said Camp Bastion was so easily entered because American and British forces had decided to "scale back" perimeter patrols and some watchtowers weren't manned.