WASHINGTON (AP) - When Marines from Camp Lejeune, N.C., were preparing for their upcoming deployment to the Middle East, they faced an unusual challenge: the beach they needed to train on had been washed away by Hurricane Florence.

Using bulldozers and other equipment, they moved enough sand to rebuild a portion of Onslow Beach so Marines could practice moving on and off landing craft and get certified for their deployment. But almost immediately afterward, the ocean swept away the sand.

Marine leaders are saying it will cost around $3.6 billion to repair the extensive damage to Camp Lejeune caused by the September hurricane that destroyed hundreds of buildings and facilities on the major East Coast base and spawned massive flooding and coastal erosion. That damage, they said, has made it harder to train forces for overseas deployments.

"We had to go through extraordinary efforts just to clear a patch of the beach so we could certify the 22nd Marine Expeditionary Unit that will deploy next week," Marine Lt. Gen. Mark Brilakis said in an interview Thursday with The Associated Press. "Marines are can-do. We went out and made that happen."

But he said it's only a temporary solution. "We pushed a lot of sand around, and a lot of that sand went back into the ocean. So we're only going to be able to repeat that a couple times, if that, before we just don't have the sand available to create that kind of capability," said Brilakis, commander of U.S. Marine Corps Forces Command.

Marines conduct exercises twice a year in order to get certified prior to deployment. Part of that training involved bringing ships -- such as landing craft -- down to Lejeune from Norfolk, so that troops can rehearse combat landings and other mission drills. The beach must be wide enough to accommodate the ships, but the storm washed too much of it away.

In addition to the beach, the more than 30 inches of rain that flooded the region washed out roads and knocked down trees, blocking access to training ranges. And a number of hangars were damaged, causing maintenance delays.

Meanwhile, nearly 5,000 military personnel and family members at Camp Lejeune were displaced, as their homes were destroyed or roofs damaged. Hundreds of other buildings were also damaged by the wind and rain, causing mold that also must now be removed.

Gen. Robert Neller, commandant of the Marine Corps, told senators this week that a number of the buildings are so old that it isn't cost effective to repair them. Instead, he said they should be rebuilt. Brilakis said that a lot of the newer buildings on the base were better able to withstand the storm, so it makes sense to put in new construction that will be up to current codes.

Hurricane Michael, which made landfall in the Florida Panhandle in October, heavily damaged Tyndall Air Force Base, and that price tag, said Sen. Tim Kaine, D-Va., is about $5 billion. It's not yet clear what funding Congress may provide for the storm repairs.

Brilakis said his priority is to make sure his Marines are ready to fight.

"We will continue to do the things we need to do to get our forces ready," he said. "But I may not get the resources that I need to be able to ensure the readiness that's been asked for in the national defense strategy."