China, Japan and South Korea agreed to jointly respond to US tariffs, a social media account affiliated with Chinese state media said on Monday, an assertion Seoul called "somewhat exaggerated", while Tokyo said there was no such discussion.

The state media comments came after the three countries held their first economic dialogue in five years on Sunday, seeking to facilitate regional trade as the Asian export powers brace against US President Donald Trump's tariffs.

All three sides agreed to strengthen supply chain cooperation and engage in more dialogue on export controls, the post said.

When asked about the report, a spokesperson for South Korea's trade ministry said "the suggestion that there was a joint response to US tariffs appears to have been somewhat exaggerated," and referred to the text of the countries' joint statement.

During Sunday's meeting, the countries' trade ministers agreed to speed up talks on a South Korea-Japan-China free trade agreement deal to promote "regional and global trade", according to a statement released after the meeting.

"The three countries exchanged views on the global trade environment, and as you can see in the joint statement, they shared their understanding of the need to continue economic and trade cooperation," the South Korean trade ministry spokesperson said.

The countries' trade ministers met ahead of Trump's planned announcement on Wednesday of more tariffs in what he calls "liberation day", as he upends Washington's trading partnerships.

Beijing, Seoul, and Tokyo are major US trading partners, although they have been at loggerheads amongst themselves over issues including territorial disputes and Japan's release of wastewater from the wrecked Fukushima nuclear power plant.