Key Asian stock markets tumbled upon opening on Monday as the world’s reaction to President Donald Trump’s tariffs campaign continued — and as U.S. futures signaled more turmoil for American markets.

Tokyo’s Nikkei 225 index lost nearly 9% shortly after the market opened, the steep decline triggering a circuit breaker that temporarily halted trading. Japan’s broader TOPIX index sank 8%.

South Korea’s KOSPI index fell more than 5% in Monday trading, with Australia’s S&P/ASX 200 sliding more than 6% before recovering slightly.

Hong Kong’s Hang Seng Index opened down 9.56%, with Chinese tech stocks like Alibaba and Baidu falling almost 12%. On the mainland — where there are fewer international investors — the Shanghai Composite Index dropped 4.82%

India’s stock markets also struggled. The BSE’s Sensex dropped 5.19% while the broader Nifty tumbled 5%.

U.S. futures signaled further weakness. Futures for the S&P 500 lost 4.2% while those for the Dow Jones Industrial Average shed 3.5%. Nasdaq futures lost 5.3%.

Investors are bracing for continued market turmoil on Monday in response to Trump’s “Liberation Day” tariffs announced last week.

Speaking with reporters on Air Force One on Sunday, Trump addressed the recent market turbulence and subsequent fears of an imminent recession.

“Now what’s going to happen with the market? I can’t tell you, but I can tell you, our country has gotten a lot stronger, and eventually it’ll be a country like no other, it’ll be the most dominant country economically in the world,” Trump said.

“I don’t want anything to go down, but sometimes you have to take medicine to fix something and we have such a horrible — we have been treated so badly by other countries because we had stupid leadership that allowed this to happen,” the president added.

ABC News’ Ellie Kaufman, Karson Yiu, Zunaira Zaki and Hannah Demissie contributed to this report.