(Updates prices, add background)

By Luoyan Liu and Andrew Galbraith

SHANGHAI, May 6 (Reuters) – Chinese investors, caught off guard by U.S. President Donald Trump’s tariff threats, dumped stocks and sold the yuan currency on Monday as a fresh deterioration in Sino-U.S. trade tensions roiled Asian financial markets.

The country’s major stock indexes were heading for their worst daily loss in three years, with the blue-chip CSI300 index and the Shanghai Composite Index tumbling more than 5 percent.

Hong Kong’s Hang Seng index slumped more than 3 percent.

Trump stunned global markets with a tweet late on Sunday announcing he would hike U.S. tariffs on $200 billion worth of Chinese goods this week and target hundreds of billions more soon, saying trade talks with China