Chinese share markets tumbled after US President Donald Trump announced plans to raise tariffs on imports from China at the end of the week, dealing a blow to hopes of an imminent end to their trade war.

The benchmark Shanghai Composite Index fell 5.58%, or 171.88 points, to 2,906.46, while the Shenzhen Composite Index, which tracks China's second exchange, plummeted 7.38%, or 120.79 points, to 1,515.80.

The Chinese yuan also took a battering after President Trump threw a spanner into the high-level negotiations, which many observers were expecting to wrap up imminently.

"For 10 months, China has been paying Tariffs to the USA of 25% on 50 Billion Dollars of High Tech, and 10% on 200 Billion Dollars of other goods," Mr Trump tweeted last night. "The 10% will go up to 25% on Friday."

The warning will throw a shadow over the next round of talks, with a delegation from Beijing due in Washington this week, with Bloomberg News reporting the Chinese side are considering their position.

The two sides have imposed tariffs on $360 billion in two-way trade since last year. But President Trump and his Chinese counterpart Xi Jinping agreed a truce in December, helping fan a surge across world stock markets for the past four months.

"Trump has taken the proverbial sledgehammer to the walnut this morning and the only two words likely to be on the minds of traders and investors this week are 'trade talks'," said OANDA senior market analyst Jeffrey Halley.

News that the People's Bank of China would slash the amount of cash lenders must keep in reserve, to support small businesses, had little impact in the face of Mr Trump's warning.

Singapore was off 3.3% and Taipei shed 1.8%, while Sydney and Wellington were each 1% down.

Manila and Jakarta were also sharply lower. Tokyo and Seoul were closed for holidays.

"Trade had been put to the side by many market participants," said Andrew Tilton, chief Asia-Pacific economist at Goldman Sachs.

"Market pricing assumed there would be some kind of a deal, and no further escalation in tariffs. And meanwhile the growth outlook was actually improving," he told Bloomberg TV.

Mr Trump's threat now "raises the spectre of a significant hit to growth should these tariffs escalate and should the uncertainty associated with that weigh on investment going forward."

"Investors will remain bearish on the yuan, as they reprice in trade war risks because the new developments are a reversal of previous positive progress," Ken Cheung, senior foreign-exchange strategist at Mizuho Bank. "The news was unexpected."

Mr Trump's outburst overshadowed another blockbuster US jobs report on Friday that reinforced the view that the economy is in rude health, while measured wage inflation eased pressure on the Federal Reserve to hike interest rates.