The U.S. is requesting that South Korea pay 1.2 billion U.S. dollars a year towards their defense cost sharing.
This is around 1.3 times more than what Seoul is currently paying.
According to Arirang's sources on Wednesday the U.S. had asked for a whole new figure of 1.25 billion dollars in their 10th round of negotiations held in December last year.
This comes despite the 9 rounds of talks between Seoul and Washington last year to sign their Special Measures Agreement for the coming years.
The U.S. delegates reportedly added that the order is said to have come "from the top."
To this, the South Korean delegates reportedly said that the South Korean people's psychologically acceptable figure is under 1-trillion Korean won, which is 886-million dollars.
This is still 35-million dollars more than what Seoul paid last year.
The U.S. reduced their request to 1.2 billion dollars, but told South Korea that they cannot accept anything less than 1-billion dollars.
The two are also known to have big differences over the length of the agreement.
Due to various issues including efficiency, the allies had been agreeing to 5-year deals from 2008.
The latest deal was implemented in 2014 and expired at the end of 2018.
However, at the 10th round of talks, sources say, Washington requested that the agreement last for only one year.
Seoul said that was unrealistic, and pushed for the usual 5 years or 3 years.
The South Korean delegates had high hopes of reaching an agreement in their 10th sitdown, as they seemed to be finding some middle ground in their previous session.
But Washington's whole new request came as a surprise, and the Korean delegates are said to have expressed strong regret over it, with no final agreement reached.
South Korea's foreign affairs ministry said it is currently working with the U.S. at various levels to come to an agreement.
The Special Measures Agreement covers the cost of American troops stationed in South Korea, which includes areas like payroll for South Koreans in the U.S. bases, construction and logistics.
Under the previous deal, South Korea contributed around 850 million dollars in 2018, with the inflation rate taken into account.
The amount is about 50 percent of the total cost.
Lee Ji-won, Arirang News.