US President Donald Trump further hardened his rhetoric towards China on Thursday, saying he no longer wishes to speak with Xi Jinping and warning darkly he might cut ties over the rival superpower's handling of the coronavirus pandemic.

Tensions have ratcheted up between Washington and Beijing as they trade barbs over the origin of the pandemic - which first appeared in late 2019 in the Chinese city of Wuhan, and which Trump has dubbed the "Plague from China."

"I have a very good relationship (with Xi), but I just - right now I don't want to speak to him," Trump told Fox Business. "I'm very disappointed in China. I will tell you that right now," he said.

Asked how the United States might choose to retaliate, Trump gave no specifics but struck a threatening tone, saying: "There are many things we could do. We could do things. We could cut off the whole relationship."

"If you did, what would happen?" Trump asked. "You'd save $500 billion if you cut off the whole relationship."

Trump has for weeks accused China of concealing the true scale of the outbreak, allowing it to spread unchecked across the globe and claim the lives of 300,000 people to date.

Beijing strongly denies the charge, insisting it transmitted all available data as soon as possible to the World Health Organization.

But Trump doubled down on Fox Business, insisting: "They could have stopped it. They could have stopped it in China where it came from. But it didn't happen that way."

"It's very sad what's happened to the world and to our country, with all of the deaths," he said.