South Korea and the United States have been discussing a shipbuilding tie-up that could include investments to modernise U.S. shipyards and more help to repair the U.S. naval fleet as Seoul seeks better tariff terms,

The agreement that Japan secured has added pressure on South Korea to defuse the threat of high tariffs on its exports to the United States.

Less than two months into his presidency, South Korean leader Lee Jae Myung is facing an early diplomatic and economic test, as his top negotiators struggle to make headway in trade talks with the US before higher levies kick in next week.