Sweeping tariffs set to be imposed by President Donald Trump next month may cast a pall over his top diplomat’s first official trip to Asia this week — just as the U.S. seeks to boost relations with Indo-Pacific nations to counter China’s growing influence in the region.

Southeast Asia's biggest economies prepared on Tuesday to step up trade negotiations with Washington after it hit them with steep tariffs, despite a last-ditch flurry of offers to boost imports and slash levies on U.