President Donald Trump has approved tariffs on Chinese goods worth about $50 billion, said a person familiar with the decision, ratcheting up a confrontation on trade with Beijing and triggering losses in the domestic stock market.

The Trump administration is preparing to release a refined list of Chinese products to be hit with tariffs that hones in on technologies where China wants to establish itself as a leader, according to five people familiar with the matter. In April, the U.S. revealed an initial list targeting about 1,300 products worth $50 billion in Chinese imports.

The U.S. is scheduled on Friday to release an updated list of Chinese tariff targets. The White House has said the duties will be implemented “shortly” after the release of Friday’s list, though no date has been set.

“Implementation of the tariffs, when it occurs, could take us closer to a trade war,” said Shane Oliver, head of investment strategy at AMP Capital Investors Ltd. in Sydney. “I suspect Trump also sees these announcements as a way of pressuring China into action on trade – so more classic Art of the Deal stuff.”

The Shanghai Composite Index dropped to its lowest since September 2016 and a whisker away from the 3,000-point mark, as markets await the looming announcement of the list of targets.

Speaking at a regular briefing on Friday, Foreign Ministry Spokesman Geng Shuang repeated China’s threat that if the U.S. unveils new tariffs then all previous agreements on trade will not come into effect. 

Geng said that U.S.-China economic ties are mutually beneficial, but warned that “if the U.S. rolls out unilateralist and protectionist measures that harm China’s interests, then we will respond immediately with necessary measures to safeguard our rights and interest.”

If actual duties are imposed after months of threats and negotiations to avert them, the world’s two largest economies will be on the verge of a full-scale trade conflict that has the potential to dent the global expansion. Aside from China, Trump has lit the fuse on trade disputes with major allies, including the European Union and Canada, and railed against the multilateral trading system with his “America First” vision.

The trade tensions are escalating at an inopportune time for China’s economy. A trio of downbeat readings on Thursday and a slump in new credit growth reported earlier in the week suggest the world’s second-largest economy is already losing some momentum. Meanwhile the U.S. economy is sprinting ahead, spurred by solid consumer spending—including May retail sales that topped forecasts on Thursday.

Trump said this week he’ll confront China “very strongly” over trade in the coming weeks. “China could be a little bit upset about trade because we are very strongly clamping down on trade,” the president said in a Fox News interview on Wednesday.

China has pledged a tit-for-tat response. In April, it said it would levy 25 percent tariffs on imports of 106 U.S. products including soybeans, automobiles, chemicals and aircraft, in response to proposed American duties.

Even as the atmosphere worsened, China still appears to be making concessions. A review of U.S. chipmaker Qualcomm Inc.’s $43 billion acquisition of NXP Semiconductors NV has been approved by Chinese regulators, according to people familiar with the matter who asked not to be identified. That deal, needing Chinese approval, had become a bargaining chip in the trade negotiations.

China and other nations should join together to counter Trump’s aggressive trade policies, the state-run China Daily said Friday, repeating past threats to retaliate in kind. While China hopes that talks can succeed in resolving the dispute, “it is high time that China and other major economies joined hands to better cope with the challenges created by the U.S.’s aggressive pursuit of trade advantages,” the editorial said.

“It’ll be a prolonged battle, not that simple that it can be solved through a few rounds of talks,” said Hu Yifan, regional chief investment officer and China chief economist at UBS Global Wealth Management.