Even as Washington ramps up pressure on Japan and South Korea to settle trade disputes with the US, diplomatic observers believe tariffs imposed by US President Donald Trump are not likely to push its two Asian allies closer to Beijing.

U.S. President Donald Trump said on Tuesday South Korea should be paying for its own military protection and suggested the U.S. ally needed to pay more for the U.S. troop presence there, a day after saying he planned to impose a 25 percent tariff on its imports.