India, July 26 -- The United States imposed new tariffs on seven Southeast Asian economies this week, just one day after US Secretary of State Marco Rubio told the same countries' foreign ministers that the US was "with ASEAN 100 per cent," a sequence of events that analysts point out has deepened perceptions across the region of Washington as an unreliable partner and has handed Beijing a diplomatic opening it is moving quickly to exploit.

Citing what it said were forced labour practices uncovered in its latest investigations, the US imposed levies ranging from 10 to 12.5 per cent on 60 economies, with the Philippines, Singapore, Thailand and Vietnam the hardest hit among Association of Southeast Asian Nations members.

Malaysia, Indone...