South Korea's new president, Lee Jae Myung, will face a pivotal moment on Monday when he meets U.S. President Donald Trump in Washington for their first summit, as the countries' decades-old alliance strains to confront rapid geopolitical changes.

South Korean President Lee Jae Myung is set to meet US President Donald Trump today to hold talks on trade and defence cooperation. The August 25 summit comes after a July trade deal where Washington agreed to bring down its reciprocal tariff on South Korea to 15 per cent from the earlier proposed 25 per cent and extend the reduced rate to South Korean cars,