CAMP LEJEUNE, N.C. — More than six months after Hurricane Florence ravaged North Carolina, hundreds of buildings at Camp Lejeune and two other nearby Marine Corps installations remain frozen in time, with walls still caved in and roofs missing.

The Marines say they need $3.6 billion to repair the damage to more than 900 buildings at Camp Lejeune, Marine Corps Air Station New River, and Marine Corps Air Station Cherry Point caused by the storm and catastrophic flooding in its aftermath. And while they have torn down soggy, moldy walls, put tarps on roofs and moved Marines into trailers, so far they have not received a penny from the federal government to fix the damage.

Now the Marine Corps' top officer is warning that readiness at Camp Lejeune — home to one third of the Corps' total combat power — is degraded and "will continue to degrade given current conditions." In a recent memo to Navy Secretary Richard Spencer, Commandant Gen. Robert Neller cited, among other "negative factors," the diversion of resources to the border, where the Trump administration has sent active-duty troops to patrol and plans to use military funding to pay for a wall.

The globe and anchor stand at the entrance to Camp Lejeune, N.C. Allen Breed / AP file

"Mister Secretary, I am asking for your assistance," wrote Neller in his memo, his second this year requesting that Spencer push Congress to provide more funds. "The hurricane season is only three months away, and we have Marines, Sailors, and civilians working in compromised structures."

Neller wrote that the lack of the money needed for repairs, and unexpected expenses like the U.S. military mission at the southern border, are "imposing unacceptable risk to Marine Corps combat readiness and solvency."

The Department of Defense has allocated money for repairs, but not until fiscal year 2020. Congress has not responded to Neller's appeal for more money in the interim.

In a March 23 memo obtained by NBC News, Acting Secretary of Defense Patrick Shanahan requested congressional approval of $600 million for "near-term hurricane recovery actions." A defense official said as much as $400 million of that could go to Camp Lejeune recovery efforts.

"We understand the effect on readiness if Congress does not approve the reprogamming action," Shanahan wrote.

In a statement to NBC News, Sen. Richard Burr, R-N.C., said it is "unacceptable" that "Camp Lejeune and other North Carolina military bases are still waiting on disaster relief we first requested last fall."

Roof damage caused by Hurricane Florence inside one of the buildings at Camp Lejeune. NBC News

Burr's fellow North Carolina Republican, Sen. Thom Tillis, agreed, telling NBC News in a written statement that "Camp Lejeune suffered significant damage from Hurricane Florence and Senators Tillis and Burr are working with Congressional appropriators to secure additional federal relief to ensure training and readiness will not be impacted in the long-term and the base can make a complete recovery."

Frogs in the hallway

At Camp Lejeune's Second Marine Expeditionary Force headquarters, roughly half the structures received significant structural damage and most of the roofs were blown off. They are still covered with blue tarps. Second MEF -- or II MEF, as it is usually known -- is one of three MEFS around the world, and represents a third of the Corps ready combat strength.

"We're 100 percent operational," said Col. Brian Wolford, chief of staff to II MEF. "We're here doing our work. But the conditions we're working under are just like when we were in Iraq or Afghanistan."

Wolford was among the first Marines back into the building after the storm, and describes seeing frogs in the hallways when they first returned.

"Is this the way we want our Marines and civilian Marines to be working?" he asked. "In these kind of conditions?"

A classroom inside one of the buildings damaged by Hurricane Florence on the historic Montfort Point section of Camp Lejeune, where the first African American Marines received their training during World War II. The building will be demolished because of extensive damage from mold and flooding from the roof. NBC News

As NBC News toured the damage, Marines at the main II MEF headquarters building maintained a positive attitude about their working conditions. They were anxious to show us the "creepy scarecrow" — a painting they found when they tore down damaged drywall after the storm.

During World War II, the building was a hospital and the Marines believe the scarecrow was once in the children's wing.

The devastation has forced the Marines to scale back on some training, including exercises at Onslow Beach, where amphibious training teaches Marines to attack from the land and sea.

Some buildings on base are beyond repair, with ceilings caved in, walls crumbling and mold everywhere. At Camp Johnson, which sits on historic Montford Point, on the northern side of Lejeune, the buildings have never been re-occupied, and Marines learning combat service support spend their days in classroom trailers. Montford Point, where the first African Americans received their training to be Marines during World War II, is a sacred place for the Marine Corps.

The Marine in charge of all installations says the repair delays are having an impact on performance and that he's disappointed in the response.

"I mean it's kind of like a thousand cuts right now," said Maj. Gen. Vincent Coglianese. "It has a serious impact."

"We've done all the due diligence that we [can] and we keep on waiting for further assistance," he said. "And there's different reasons why I guess we haven't got that. That's not for me to say. I'm just disappointed."

After removing damaged drywall, Marines found an old scarecrow painting, believed to be from when the building was a hospital Kube / NBC News

In December, Neller told Congress that repair of 31 prioritized buildings on the base would cost $3.6 billion. Some buildings were so old and damaged that they need to be rebuilt from the ground up, he said.

In the meantime, the Marine Corps has moved around money already in its budget to pay for small, temporary fixes.

"We've done initial, you know, damage control surgery and triage," said Brig. Gen. Ben Watson, the commanding general for Camp Lejeune. "But we haven't got the funding yet to actually repair the buildings."

Watson knows another hurricane or severe rain could change everything, making difficult working conditions untenable.

"Marines will find a way to accomplish the mission," he said. "It just becomes harder and harder. And we ask more and more of our service members and their families to accomplish the same mission."

The next hurricane season begins on June 1. Gen. Neller is expected to retire from the Marine Corps by then, after 44 years of service. Lt. Gen. David H. Berger has been nominated to replace him.