China announced additional tariffs on 106 U.S. products on Wednesday, in a move likely to heighten global concerns of a tit-for-tat trade war between the world's biggest economies.
The effective start date for the new charges will be revealed at a later time, though China's Ministry of Commerce said the tariffs are designed to target up to $50 billion of U.S. products annually.
The 25 percent levy on U.S. imports includes products such as soybeans, cars and whisky, Beijing said.
The move comes less than 24 hours after President Donald Trumpunveiled a list of Chinese imports that his administration aims to target as part of a crackdown on what the president deems unfair trade practices.
Sectors covered by Trump's proposed tariffs include products used for robotics, information technology, communication technology and aerospace.
The trade showdown between Washington and Beijing has rattled investors and fueled market fears that the dispute could soon spiral into a full-blown trade war.
When asked whether global markets were now officially observing an all-out trade war, Goldman Sachs' chief global equity strategist, Peter Oppenheimer, told CNBC: "I think it is clearly a trade battle at the very least."
"I think the anxiety the market is reflecting is that it could escalate into a generalized (trade) war," he added.
China's proposed countermeasures prompted U.S. stock index futures to tumble ahead of Wednesday's open. At around 5:15 a.m. ET, Dow futures sank 419 points, indicating a drop of 438.36 points at the open. The Nasdaq and the S&P 500 futures also indicated heavy losses at the open for their respective markets.
Meanwhile, Wednesday's announcement also prompted European stocks to extend losses, with the pan-European Stoxx 600 hitting a session low of 0.8 percent shortly after the news.