The United States and South Korea have failed to agree on a bigger South Korean share of the cost of maintaining U.S. troops, an official said on Friday, as the U.S. military warned Korean workers they might be put on leave if no deal is reached.

U.S. President Donald Trump has repeatedly said that South Korea should bear more of the burden for keeping some 28,500 U.S. troops in South Korea, where the United States has stationed forces since the 1950-53 Korean War.

Senior officials from both sides held three-day talks in Seoul from Tuesday to hammer out an accord to replace a 2014 deal due to expire this year, which requires South Korea to pay about 960 billion won ($850 million) this year.