Light-vehicle sales in the world's biggest auto market fell 3.6 percent from the same month a year earlier, the China Association of Automobile Manufacturers said.

The ongoing discussions illustrate the difficulties in reaching an accord that President Donald Trump said more than eight weeks ago was basically done and would take three to five weeks to put on paper.

VinFast follows a long list of Chinese automakers that have also had ambitions to sell vehicles in the U.S. going back more than a decade. 

Volkswagen Group and SAIC Motor Corp. invited parts makers to bid to become suppliers for an Audi A7L they plan to build, signaling the German luxury brand is poised to add China’s largest automaker as a manufacturing partner as Audi pushes to regain share lost to Mercedes-Benz and BMW in the world’s biggest market.