Southeast Asian nations are scrambling to recalibrate their approach to US tariffs ahead of a key diplomatic gathering that starts in Kuala Lumpur on Tuesday, as Washington’s preference for one-on-one trade deals casts doubt over Asean’s collective bargaining power.

US President Donald Trump on Sunday announced a delay to the next round of his sweeping “Liberation Day” tariffs – pushing the deadline from July 9 to August 1 – to give time for finalising deals with 18 major trade partners, including the European Union and India .

One such agreement, struck with Vietnam last Thursday, slashed tariffs by more than half to 20 per cent in exchange for duty-free access for US exports and a hefty 40 per cent levy on goods re-exported through Vietnam’s ports from third countries.

That deal – with the US’ 10th largest trade partner – undercut the Association of Southeast Asian Nations ’ earlier push for a united front in dealing with the tariff regime, observers said, leaving the rest of the bloc’s members more vulnerable to direct pressure from Washington.