South Korea and the United States will hold their fourth round of negotiations on sharing the cost for the upkeep of the 28,500-strong American troops here, a foreign ministry official said Monday.

The talks on the Special Measures Agreement will take place in Seoul from Tuesday through Thursday, led by Lee Tae-woo, South Korea's chief negotiator for the talks, and Linda Specht, the US lead negotiator for security agreements at the State Department, the official said.

The current six-year SMA is due to expire at the end of next year.

"We plan to proceed with the negotiations based on the position that our share of the defense cost should come at a reasonable level to create an environment for a stable stationing of the US Forces Korea and to strengthen the Korea-US combined defense posture," the official said.

The upcoming talks come about two weeks after they had the third round of the talks in Washington.

The allies launched the negotiations in April, earlier than expected, amid speculation that Seoul wants an early deal to avoid tough bargaining with Washington in case former President Donald Trump returns to the White House.

The two sides haggled over the payment during the previous talks under Trump's presidency, as Washington had demanded more than a fivefold increase in Seoul's payment to $5 billion.

Under the latest SMA, South Korea agreed to a 13.9 percent increase in the payment to $1.03 billion for 2021 and to increase the payment every year for the subsequent four years in line with the rise in Seoul's defense spending.

Since 1991, Seoul has partially shared the cost for Korean USFK workers; the construction of military installations, such as barracks, as well as training, educational, operational and communications facilities; and other logistical support. (Yonhap)