HONG KONG — The risk that a trade war between China and the United States was entering a dangerous new phase sent global markets lower again on Thursday.
Stocks on Wall Street, which fell more than 3 percent on Tuesday, again slid into negative territory for the year, opening more than 1 percent lower. United States markets were closed on Wednesday in observance of President George Bush’s funeral.
The drop on Thursday followed the arrest of a prominent Chinese technology executive at the request of the United States, which appeared to dash hopes that a trade-war cease-firereached between the economic giants over the weekend would last.
In recent days, doubts and confusion about that truce have grown, sending markets lower. But news that the chief financial officer of the Chinese tech giant Huawei, Meng Wanzhou, had been arrested in Canada raised fresh uncertainty, not only about the truce, but about the possibility that new phase in the trade war posed substantial risks for the tech companies that have driven major gains for American investors in recent years.
Ms. Meng was arrested in Vancouver on Saturday, even as President Trump and President Xi Jinping of China were dining together in Buenos Aires and agreeing to a 90-day pause in their countries’ trade war. The arrest was expected to renew tensions.
All major markets in Asia ended the trading day down more than 1 percent, and several slid further. Results were grimmer in Europe, where major indexes in London, Frankfurt and Paris had hit their lowest levels in about two years by late morning.
In Asia, the tone for the day was set in Hong Kong, where investors rattled by Ms. Meng’s arrest focused their attention on technology stocks and the overall market dropped 2.5 percent. The shock wave was felt across the border in Shenzhen, where stocks fell 2.2 percent.
In Tokyo, the market fell nearly 2 percent after the governor of the Bank of Japan warned that the trade war would hurt the Japanese economy. Traders in Seoul, South Korea, pushed the market down more than 1.5 percent; stocks in Taiwan were down 2.3 percent.
Concerns persist that the tensions between the United States and China could further slow a global economy already showing signs of cooling.
“The world economy is still expanding at a rapid pace, but cracks are starting to appear in the global growth picture,” Brian Coulton, a chief economist at Fitch Ratings, wrote in a note to clients. Fitch has repeatedly warned of China’s debt binge and the challenges facing the second-largest economy after the United States.
The week began an optimistic note, with the announcement that Mr. Trump and Mr. Xi had reached a deal on the sidelines of the Group of 20 meeting. Stocks around the globe soared on the news.
But a series of tweets from Mr. Trump, who called himself “a Tariff Man” prompted a new round of selling.
The only thing that seems certain is more uncertainty, analysts said.
“While the likelihood of an ongoing dialogue after months of no discussions and the pause on tariffs are still positive developments, it’s clear that negotiations will be challenging and a source of volatility,” Mark Haefele, chief investment officer at UBS wealth management, said in a note to clients.