Biarritz, France | Injecting fresh uncertainty at a time of global economic jitters, US President Donald Trump sent mixed messages on Sunday (Monday AEST) on the US-China trade war as G7 leaders pushed unsuccessfully on the unpredictable president to ease frictions on tariffs.

Mr Trump's head-snapping comments at the summit about his escalating trade fight with China – first expressing regret, then amping up tariff threats – represented just the latest manifestation of the hazards of the president's go-it-alone mantra. Allies fault his turbulent trade agenda for contributing to a global economic slowdown.

AAP