South Korea and the United States held a second day of talks on sharing the cost of stationing American troops here on Wednesday as US President Donald Trump renewed calls for allies to pay their "fair share."

The two sides launched the negotiations on Tuesday to renew the Special Measures Agreement on determining how much Seoul should pay for stationing some 28,500 US soldiers in the country.

The current deal is set to expire on Dec. 31.

During the first day of talks, the two sides exchanged their basic stances, officials said without providing details. The talks were led by Chang Won-sam, interim chief negotiator for South Korea, and his American counterpart, James DeHart.

The next round of the talks is expected to take place in the US in October.

Trump has long demanded Seoul pay more for the US troop presence, highlighting his position again during his speech to the UN General Assembly on Tuesday (US time).

"We are also revitalizing our alliances by making it very clear that all of our partners are expected to pay their fair share of the tremendous defense burden which the United States has borne in the past," Trump said. 

The defense cost-sharing issue was also discussed when South Korean President Moon Jae-in and Trump held summit talks on the sidelines of the UN gathering on Monday. 

Moon stressed that the cost should come at a "fair and reasonable" level.

Under this year's SMA, signed in February and valid until Dec. 31, South Korea agreed to pay 1.04 trillion won ($868 million), an increase of 8.2 percent from the previous year.

Since 1991, Seoul has shouldered partial costs under the SMA -- for Korean civilians hired by the USFK, the construction of military facilities to maintain the allies' readiness and other forms of support. (Yonhap)