South Korea's chief negotiator Jeong Eun Bo answers a reporter's question after a meeting with U.S. counterpart James DeHart at…
FILE - South Korea's chief negotiator Jeong Eun Bo talks to reporters after a meeting with U.S. counterpart James DeHart at Foreign Ministry in Seoul, South Korea, Nov. 19, 2019.

SEOUL - The United States and South Korea failed to reach a defense cost-sharing agreement after holding a fourth round of talks this week.

Jeong Eun-bo, South Korea's head negotiator in the defense cost-sharing talks, met with U.S. officials for two days in Washington this week. By the end of his trip, the two countries had not reached any conclusions, he said.

"At this point, we are in a situation where we need to continue to narrow our differences. It is not that we have reached a concrete result," Yonhap reported that Jeong said at Dulles International Airport on Dec. 6.

FILE - U.S. soldiers wait for a speech by U.S. President Donald Trump (not pictured) as he meets U.S. troops based in Osan Air Base, South Korea, June 30, 2019.

Since meeting in Honolulu last October, U.S. negotiators have asked that South Korea pay roughly $5 billion to cover the cost of the 28,500 U.S. troops stationed there. That's five times the roughly $800 million amount South Korea is currently paying. It appears that the United States is still asking for Seoul to pay the sharp increase — even after South Korea agreed to increase its share of the cost burden by 8.2% last February. South Korea also agreed to cover roughly 90% of the $10.7 billion cost to relocate a U.S. military base away from Seoul and allow the base to operate rent-free.

"It is right to say that the U.S. maintains its position," Jeong said. "We will try hard to conclude the negotiations by the year's end."

Despite the disagreements, the U.S. and South Korea are forced to work under a tight deadline. The current Special Measures Agreement (SMA) is set to expire at the end of the year.

Jeong and the top U.S. negotiator, James DeHart, will meet later this month in Seoul to further talk defense cost-sharing, according to several South Korean media reports.