WASHINGTON -- The US State Department has named a new envoy for defense cost-sharing negotiations with South Korea and other nations, a department spokesperson said Monday.

Donna Welton, who recently served as assistant chief of mission at the US Embassy in Afghanistan, will succeed Jim DeHart, who was appointed last week as the US coordinator for the Arctic region.

"As Mr. DeHart's successor, Ms. Welton will pick up where Jim left off in regards to the ROK Special Measures Agreement, the Japan Host Nation Support Agreement, and all other defense cooperation and burden sharing negotiations we conduct worldwide," the spokesperson told Yonhap News Agency, referring to South Korea by its official name, the Republic of Korea.

Defense cost-sharing negotiations between Seoul and Washington have been deadlocked for months amid US demands for a significant increase in South Korea's contribution to the cost of stationing 28,500 American troops on the peninsula.

Under the previous one-year agreement, which lapsed at the end of December, South Korea agreed to pay $870 million.

This year the US is known to be requesting $1.3 billion a year, a 50 percent increase on last year, while South Korea maintains it can only increase its payment by 13 percent.

Japanese media reported Welton's appointment earlier, saying she will lead negotiations for the two countries' defense cost-sharing agreement, which is due for renewal in March.

Welton is known as an expert on Japan with a fluent command of Japanese. She previously served in Tokyo, Nagoya and Sapporo, Japan, and also worked as a curator of Japanese art at the Metropolitan Museum of Art in New York.

As a diplomat, Welton has over 25 years of experience and has worked in countries including Finland and Indonesia and at the US mission to the United Nations. The spokesperson later added that Welton has also served in South Korea.

She has studied Korean, Indonesian and German, among other languages.

The personnel shift comes amid renewed speculation the US may pull troops from South Korea if the defense cost-sharing negotiations continue to stall.

The Wall Street Journal recently reported that the Pentagon presented the White House with options to reduce troops in South Korea in March.

"President (Donald) Trump has already rejected a tentative agreement once, so it's unclear how much discretionary power a new negotiator will have," a diplomatic source said, referring to an earlier near-deal to increase Seoul's contribution by 13 percent. (Yonhap)