Asia-Pacific markets set to fall after Trump says he plans to double steel tariffs to 50%

Asia-Pacific markets were set to fall after President Donald Trump told U.S. steelworkers late Friday that he will double tariffs on steel imports to 50% with effect from Wednesday.

Japan's benchmark Nikkei 225 was set to open lower, with the futures contract in Chicago at 37,650 while its counterpart in Osaka last traded at 37,680, against the index's last close of 37,965.1.

Futures for Hong Kong's Hang Seng index stood at 22,901, lower than its last close of 23,289.77.

China, Malaysia and New Zealand markets are closed for the holidays.

"We're going to bring it from 25% to 50%, the tariffs on steel into the United States of America," Trump said during remarks at U.S. Steel's Irvin Works in West Mifflin, Pennsylvania, adding that the steep tariffs would "further secure the steel industry."

Trump also posted on Truth Social that the steel tariffs will start on June 4.

U.S. stock futures fell as Wall Street looks to the start of a new month of trading following a strong performance in May. S&P 500 futures traded down 0.3%, along with Nasdaq-100 futures. Futures tied to the Dow Jones Industrial Average also declined 108 points, or 0.3%.

Last Friday, the three major averages closed mixed. The S&P 500 was little changed on Friday to close out a big winning month, inching down by 0.01% to end at 5,911.69. The Nasdaq Composite slid 0.32% to 19,113.77, while the Dow Jones Industrial Average added 54.34 points, or 0.13%, to finish at 42,270.07.

— CNBC's Brian Evans and Alex Harring contributed to this report.