US National Security Advisor John Bolton is expected to visit South Korea next week amid worsening relations between the country and Japan.
US and South Korean sources say arrangements are being made for Bolton's two-day visit to South Korea from next Tuesday. He's expected to stop in Japan first.
Tokyo and Seoul remain at odds over wartime labor issues and Japan's stricter export controls.
South Korea's government has not accepted Japan's request to launch an arbitration panel, based on a 1965 bilateral agreement, to settle their wartime labor dispute.
South Korean courts ordered Japanese companies to compensate workers who say they were forced to work for them during World War Two.
On the economic front, Seoul has criticized Tokyo for its decision to tighten control of exports of sensitive high-tech materials to the South.
The sources say Bolton will likely encourage the two sides to sit for dialogue and resolve the issues.
On Wednesday, US diplomat in charge of East Asia policy David Stilwell met South Korean foreign minister Kang Kyung-wha and other officials in Seoul.
Stillwell said the United States, as a close friend and ally to both, will do what it can to support their efforts to resolve the situation.