The move, he said shows "once again that we stand in constant vigilance in support of free, fair, and reciprocal trade". US companies and industries claiming injury from imports would normally first ask the Commerce Department to open such probes, but government-initiated cases skip that step.
In an action that hasn't been taken for more than 26 years, U.S. Secretary of Commerce Wilbur Ross announced that his agency was beginning the self-initiated investigation of antidumping duties (AD) and countervailing duties (CVD) associated with alloy aluminum sheet from China. These imports to the US totaled $603.6 million in 2016.
China responded Wednesday by saying the move was "rare in the history of global trade". Antidumping duties are assessed when an imported product is being sold below market value, and harming competitors in the process.
Wang also said China would take necessary measures to safeguard the rights and interests of Chinese enterprises.
"Available evidence also indicates that USA producers of aluminum sheet are suffering injury caused by these imports", Ross said.
China expressed its "strong dissatisfaction" at the move, with its Ministry of Commerce saying in a statement on Wednesday the action would hurt both countries' interests.
In a complaint to the World Trade Organisation in December, China argued against the use of "analogue pricing" standards used by the U.S. and the European Union to determine anti-dumping duties on Chinese goods. It is the first such case the US government has begun on its own since it launched an investigation into Canadian softwood lumber imports in 1991.
Washington's use of the rare tactic capped a series of adversarial manoeuvrers on trade with China and came shortly after President Donald Trump's two-week trip to Asia this month, which included a stop in Beijing.
In April, Trump directed the Commerce Department to investigate whether imports of aluminum threaten America's national security. The last self-initiated anti-dumping investigation was into Japanese semiconductors in 1985. If the Commerce Department determines that the aluminum in question is either being dumped or receiving unfair government subsidies, it can impose duties on those products to compensate for any competitive advantage.
The Trump administration has launched 65 percent more trade investigations than the final year of the Obama administration, with 79 opened compared to just 48 in 2016, according to the Commerce Department.
"I believe that this investigation reduces even further in my view the chances of duties on primary aluminum via Section 232, because its complaints are focused on China", he said.