WASHINGTON: The US military has begun to investigate a Taliban attack on a US-British base in Afghanistan last September that killed two Marines and destroyed six aircrafts and put on hold the announced promotion of the two-star Marine general who was in charge there at the time, officials said Thursday.

Marine Maj. Gen. Charles M. Gurganus was the senior commander in southwestern Afghanistan when 15 Taliban fighters breached the security perimeter of Camp Bastion in Helmand province and carried out their stunning attack. All but one of the fighters was killed in a Marine counterattack.

Gurganus earlier this year was picked for promotion to lieutenant general and assignment as director of the Marine Corps staff at the Pentagon. A Pentagon official said Thursday that his promotion has been placed on hold pending the outcome of the Central Command investigation. The official spoke on condition of anonymity because he was not authorized to discuss the matter publicly.

A few weeks after the Sept. 14 attack, Gurganus told a news conference that "there's no mystery" to how the Taliban managed to get onto the supposedly secure base and launch their deadly attack using rocket-propelled grenades.

Gurganus said they used simple wire cutters to penetrate the perimeter fence, which was not equipped with alarms. "We have sophisticated surveillance equipment, but it can't see everywhere, all the time," he said. "This was a well-planned attack. I make no excuses for it. This was well planned and it was well executed."

In fact, at least one of the guard towers near the Taliban fighters' entry point was unoccupied at the time, officials have said.

Despite the loss of two Marines and the destruction of almost an entire squadron of Marine AV-8B Harrier jets valued at about $200 million, no formal investigation was undertaken to determine whether anyone should be held to account for failing to stop one of the most audacious attacks of the war.

Killed in the attack were Lt. Col. Christopher Raible, 40, and Sgt. Bradley Atwell, 27.

Britain's Prince Harry, a helicopter pilot, was serving at Camp Bastion at the time of the attack. Officials said he received additional protection when the attack occurred.

At the recommendation of Gen. James Amos, commandant of the Marine Corps, a US Central Command investigation was ordered this week by Army Gen. Lloyd Austin, the head of Central Command, according to his spokesman, Oscar Seara.

Austin ordered that the probe report on "any fault, negligence or failure of responsibility by US commanders and staff" responsible for security at the base, which is surrounded by open terrain and adjacent to the Marine's main base, known as Camp Leatherneck. Because Leatherneck does not have a runway, Marine aircraft use Bastion's airfield headquarters in Helmand.

The Washington Post was first to report that Central Command had opened an investigation.

Seara said Austin determined that a formal investigation was warranted to "ensure all matters of US accountability have been appropriately addressed."