President Donald Trump and China’s President Xi Jinping shake hands at a press conference following their meeting outside the Great Hall of the People in Beijing last November. (Photo, Getty Images)

President Donald Trump warned China on Saturday that it should strike a trade deal with the United States now, otherwise an agreement would be "far worse for them if it has to be negotiated in my second term."

Washington and Beijing are locked in a trade battle that has seen mounting tariffs, sparking fears the dispute will damage the global economy.

Two days of talks ended Friday with no deal. China's top negotiator said the two sides would meet again in Beijing at an unspecified date, but warned that China would make no concessions on "important principles."

"I think that China felt they were being beaten so badly in the recent negotiation that they may as well wait around for the next election, 2020, to see if they could get lucky and have a Democrat win -- in which case they would continue to rip-off the USA for Sh50.6 trillion (USD500 Billion) a year," Trump said in a tweet Saturday.

"The only problem is that they know I am going to win (best economy and employment numbers in U.S. history, and much more), and the deal will become far worse for them if it has to be negotiated in my second term. Would be wise for them to act now, but love collecting BIG TARIFFS!"

Trump had accused Beijing of reneging on its commitments in trade talks and ordered new punitive duties, which took effect Friday, on Sh20.2 trillion (USD200 billion) worth of Chinese imports, raising them to 25 per cent from 10 per cent.

He then cranked up the heat further, ordering a tariff hike on almost all remaining imports – Sh30.3 trillion (USD300 billion) worth, according to US Trade Representative Robert Lighthizer -- from the world's second-biggest economy.

Those tariffs would not take effect for months, after a period of public comment.

Trump also said Saturday that firms could easily avoid additional costs by producing goods in the United States.

"Such an easy way to avoid Tariffs? Make or produce your goods and products in the good old USA. It's very simple!" he tweeted, echoing a similar message he sent Friday -- and even retweeted.

Only a week earlier, the United States and China had seemed poised to complete a sweeping agreement.

Washington wants Beijing to tighten its intellectual property protections, cut its subsidies to state-owned firms and reduce the yawning trade deficit; China wants an end to tariffs as part of a "balanced" deal.

While supporters laud Trump as a tough negotiator, free-trade-minded Republicans have warned that the tariffs could do real damage to the economy, and many farmers -- including Trump supporters -- say the tariffs have hit their bottom line.

As the trade war spread, China imposed Sh11.1 trillion (USD110 billion) in duties on farm exports and other US goods.

Republican Senator Chuck Grassley, from the farm state of Iowa, cautiously welcomed the new tariffs but urged negotiators to reach a quick solution "so we can avoid prolonged tariffs, which we know have an impact on the US economy."