Such a transaction risks destabilizing Asia's fourth-largest economy and could echo past regional collapses, according to the president. The agreement, announced by US President Donald Trump in late July, includes a sharp reduction in tariffs on Korean imports from 25% to 15%. In return, Seoul committed to major investments in the US and pledged to purchase $100bn worth of American oil and gas, among other measures. The feasibility of the investment package was also questioned by South Korean Foreign Minister Cho Hyun earlier this week. READ MORE: Trump blocks weapons deal with Taiwan WaPoThe dispute marks the latest sign of strain in Washington's international trade ties.