President Donald Trump, U.S. President Donald Trump's national security adviser John Bolton, U.S. Treasury Secretary Steven Mnuchin attend a working dinner with Chinese President Xi Jinping after the G20 leaders summit in Buenos Aires, Argentina December 1, 2018.

The United States kicked off the necessary process before Washington can impose tariffs on a new set of Chinese imports.

While President Donald Trump said as recently as Monday that he had still not decided whether he would slap tariffs on an additional $300 billion worth of Chinese goods, this sets the legal process in motion. The Office of the U.S. Trade Representative formally began that process with a proposal on Monday.

The USTR outlines a potential duty of up to 25% tariffs on China for goods with an annual trade value of roughly $300 billion. The committee will hold a public hearing on June 17 followed by another week for comments, meaning the earliest possible action for tariffs would be June 24. This gives the White House a window of time leading up to the G-20 Summit to decide.

The USTR unveiled a list of new items that would be subject to the potential round of tariffs. The products, published on the agency's website, include "essentially all products not currently covered" by the previous rounds of tariffs against China. It ranges from milk and animal products to steel and aluminum.

The proposed list excludes pharmaceuticals, select medical goods, rare earth materials and critical minerals. Any products given exemptions on prior tariffs "will not be affected," the agency said.

Major U.S. indexes suffered their worst trading day since January Monday after news that China plans to raise tariffs on $60 billion worth of U.S. imports, beginning on June 1. President Trump said China's retaliatory tariffs put the United States in a great position and represents "a very positive step" in the ongoing trade negotiations.

President Donald Trump tweeted on Monday that China will be "hurt very badly if you don't make a trade deal." Trump also said that China had a "great deal" almost completed — but they "backed out."

The list of current targeted goods ranges from TV cameras to tequila, and includes a range of agricultural products. Beijing's move comes after Washington announced last week it would increase tariffs from 10% to 25% on a bulk of Chinese imports.