SEOUL, Dec. 14 (Xinhua) -- South Korea and the United States failed to narrow gap in negotiations over how much Seoul would pay for the U.S. troops stationed in South Korea, local media said Friday, citing the foreign ministry.

Senior diplomats from the two allies had held negotiations in Seoul for three days through Thursday to strike a deal on the Special Measures Agreement (SMA) that stipulates the cost-sharing between Seoul and Washington for the U.S. Forces Korea (USFK).

The current five-year accord will expire at the end of this month. About 28,500 U.S. soldiers are stationed here as a legacy of the 1950-53 Korean War that ended with armistice.

A South Korean foreign ministry official was quoted as saying that the two sides failed to reach an agreement because of the still big difference in the total amount of Seoul's financial contributions.

South Korea paid 960 billion won (850 million U.S. dollars) for the stationing of the USFK, but the United States asked Seoul to sharply raise its yearly contribution, as much as to double the current amount, according to local media reports.

The failure to reach the deal has been forecast to cause a problem to about 8,000 South Korean civilian workers who are employed by the USFK. About one-third of Seoul's financial contributions is reportedly used for their wages.