South Korea's Presidential Office said Tuesday that tariff talks with the U.S. have been stalled for a while, but President Lee Jae Myung is determined not to force Korean companies to sustain losses by rushing to sign a trade deal.

The countries have been struggling to overcome obstacles to finalize a trade deal agreed in July. Details of the broad trade agreement still need to be hammered out, especially around a $350 billion investment fund.

"We cannot do everything the U.S. wants. ... Although (President Lee) aims to reach a deal as soon as possible, he is determined not to give up his role concerning the national interest in order to meet a deadline," a presidential official told reporters Tuesday.

South Korea's top trade envoy, Yeo Han-koo, is currently in the United States for follow-up tariff negotiations.

Yeo told reporters on Monday that Seoul and Washington were still engaging "intensively" in negotiations in bid to nail down a final trade deal, but the "devil is in the details," the Yonhap news agency reported.