SEOUL (Reuters) -South Korean President Lee Jae Myung told U.S. Treasury Secretary Scott Bessent that trade talks with the United States should be "commercially rational" and meet the interests of both countries, the president's office said on Thursday.

Lee spoke to Bessent at the United Nations on the sidelines of the General Assembly on Wednesday, his chief secretary for policy, Kim Yong-beom, told a briefing in New York.

The meeting focused on the $350 billion package of investment from South Korea agreed in principle between Lee and U.S. President Donald Trump at a summit in July as part of a deal to lower tariffs against South Korean goods, Kim said.

"With regard to the investment package with the U.S., (Lee) expressed hope that the discussions would progress based on commercial rationality and in a direction that serves the interests of both countries," Kim said.

He said South Korea's economy and its foreign exchange market - which differ significantly from Japan's - should be key factors in the ongoing talks on a final agreement.

Japan formalized a trade deal with the U.S. earlier in September to lower tariffs on its exports. The agreement includes Japan investing $550 billion in U.S. projects.

South Korea's Lee has said that a similar arrangement involving large capital outflow to the United States could destabilize the currency market and drain South Korea's foreign reserves.

South Korea is seeking a foreign exchange swap with an unlimited credit line from the U.S. to support any final trade agreement, Kim said. South Korean officials have said Washington is reviewing the FX swap proposal.