The head of U.S. Army Pacific at Fort Shafter and his staff have been tasked with creating a noncombatant evacuation operation plan for Americans in South Korea should war occur on the peninsula, the top military commander in the Pacific said.

Hawaii-based Gen. Robert Brown is developing what’s known as a “NEO” plan and will see it through to fruition, Adm. Harry Harris, who leads U.S. Pacific Command on Oahu, said at a congressional hearing Wednesday.

Harris said he and Gen. Vince Brooks, commander of U.S. Forces Korea, have made NEO planning “a key line of effort in what we’re both doing, because we both know that if conflict breaks out on the Korean Peninsula, we’re going to have to get the Americans off of there.”

Harris added that the numbers are “staggering” — with estimates of more than 200,000 Americans civilians in the South.

“Not military, but Americans who live and work in South Korea,” Harris said. “And then on top of that you’ve got a million Chinese that live and work on the Korean Peninsula, 60,000 Japanese and on and on and on.”

The behind-the-scenes planning is another sobering reminder of the effects of a possible war with North Korea.

Korea expert Victor Cha said in an opinion piece this month that on any given day there are 230,000 Americans in South Korea and about 90,000 in Japan.

“Given that an evacuation of so many citizens would be virtually impossible under a rain of North Korean artillery and missiles — potentially laced with biochemical weapons — these Americans would most likely have to hunker down until the war was over,” Cha wrote.

Harris, who made the comments at a hearing on military posture and security in the Pacific, said the Army and other services have moved munitions to South Korea to the point that “I’m beginning to worry about munitions storage capacity.”

The massive NEO planning effort comes amid signs of rapprochement between North and South Korea at the Winter Olympics.

But the backdrop also includes concern that a limited U.S. “bloody nose” strike on North Korea to warn Kim Jong Un of American resolve could result in war and thousands of artillery pieces firing at Seoul.

If North Korea used only conventional munitions, estimates are that between 30,000 and 300,000 would be killed in the first days of fighting, according to a Nov. 6 Congressional Research Service report.

“Complicating matters, should China choose to join the conflict, those casualty rates could grow further, and could potentially lead to military conflict beyond the peninsula,” the report said.

U.S. Rep. Anthony Brown, D-Md., said at the hearing that he had talked with U.S. commanders, and it “doesn’t seem as if we really have a NEO, a good grasp of what we need to do” in the event of war. He said he was told that “we’re starting to take a look at it.”

Harris said planning is “much further along” than just taking a look at it. “But there is work to be done,” Harris said, and that’s where U.S. Army Pacific’s Brown comes in.

Col. Christopher Garver, a spokesman for U.S. Army Pacific, said the Hawaii command has responsibility for developing the military side of the NEO plan in conjunction with the State Department, which has overall responsibility for the evacuations.

Garver said he wouldn’t get into plan specifics, which are classified, but “suffice it to say that we would be using a variety of methods and systems to try to move people off the Korean Peninsula in the event of a declaration of a noncombatant evacuation.”

Harris also said he does not subscribe to the view that Kim’s military actions are an attempt to safeguard his regime.

“I do think that he is after reunification under a single communist system. So he’s after what his grandfather failed to do and his father failed to do,” Harris said. Kim seeks what he feels is his “natural place” within a unified Korea subject to his and his regime’s rule, Harris said.