South Korea came close to agreement with the United States Saturday on its share of the cost of keeping American soldiers on its soil, officials said, indicating that a formal announcement of the deal was imminent.

   "Currently, the two sides are in the final stage of talks," a Seoul government official said. "They may be able to make an official announcement of the deal as early as tomorrow after each side reports the outcome of the talks to their respective governments."

   The allies launched talks early last year to renew their so-called Special Measure Agreement (SMA) that sets the financial burden each side should take to keep the 28,500 American troops in South Korea in the coming five years.

   As the negotiaitons dragged on, the current SMA, rewritten in 2008, expired at the end of last year.

   The latest round of negotiations, the 10th in its series, began Thursday.

   One of the most contentious issues had been how much South Korea should contribute. The U.S. had reportedly sought at least 1 trillion won (US$942 million) from South Korea, up from 869.5 billion won in 2012.

   Seoul had reportedly proposed around 900 billion won.

   In this week's negotiations, both sides compromised roughly halfway after the U.S. softened its demand and South Korea agreed to contribute around 930 billion won, according to government sources.

   Both sides were also seen to have agreed to overhaul the way the U.S. uses the defense funds in order to improve transparency in a renewed deal reportedly to last another five years.

   Civic activists and lawmakers here have demanded such measures after data showed that the U.S. is sitting on more than 1 trillion won of unspent defense funds, paid by Seoul.

   The renewal needs to be ratified by the National Assembly before going into effect.

   Experts anticipated a parliamentary controversy over the expected renewal, citing the increase in the size of local contributions.

   Since forging their first SMA in 1991, South Korea has shouldered part of the defense cost, and its share has increased every few years when the military agreement has been renewed. The last deal inked in 2009 expired last year. (Yonhap News)