SEOUL--With South Korea’s defense minister due to meet his American counterpart on Monday in Washington, the U.S. military doubled down on calls for Seoul to pay more in defense costs, warning of the implications if a deal was not made soon.

Defense Minister Kyeong-doo Jeong and U.S. Secretary of Defense Mark Esper are expected to discuss a standoff with North Korea, as well as plans to give South Korea control of the troops on the peninsula in the event of a war.

But overshadowing both those issues are negotiations over how much South Korea should pay toward maintaining the roughly 28,500 U.S. troops stations there.

The last “special measures agreement” (SMA) lapsed at the end of December after multiple rounds of talks yielded no progress, and now the U.S. military says funding will soon run out for thousands of South Korean civilians who work to support the bases.

Without such a pact, United States Forces Korea (USFK) must prepare to put around 8,700 South Korean employees on unpaid leave when money runs out on March 31, leading to some services on the bases being “degraded, suspended or canceled,” the command said in a statement on Monday.

“The potential furlough will have a significant impact--both emotionally and financially--to our Korean National employees,” USFK commander Gen. Robert Abrams added. “It will also have some negative repercussions to installation services.”

On Sunday, the Pentagon said it would continue to pay for any South Koreans who “provide life, health, safety and readiness services.”

But the furloughs may be avoided altogether if South Korea agrees to a “more equitable” SMA, the Pentagon added.

A spokesman for South Korea’s Defense Ministry declined to comment on the talks, but said the South was stepping up efforts to reach a deal as early as possible to minimize any problems.

U.S. President Donald Trump has repeatedly said South Korea should bear more of the burden for hosting the troops, a legacy of the 1950-53 Korean War which ended in an armistice, not a peace treaty.

Washington demanded up to $5 billion (557 billion yen) a year, more than five times what Seoul agreed to pay last year under a one-year deal, though U.S officials said they have “compromised” on the numbers.

The salaries of the employees who provide administrative, technical and other services for the U.S. military have typically been covered by about 70 percent of South Korea’s contribution.

“We are in unchartered waters,” Abrams said. “And we have to prepare for a potential furlough for some of our Korean National employees and finalize our planning for its impacts now.”