WASHINGTON • American companies and industry groups are returning to Washington this week in an increasingly futile effort to get relief from President Donald Trump's tariffs on Chinese imports.

More than 80 witnesses are scheduled to testify during the two-day hearing starting yesterday on the proposed second round of tariffs on US$16 billion (S$22 billion) of Chinese goods targeted for 25 per cent duties.

The US imposed the first round of tariffs on US$34 billion of products on July 6, after similar hearings in May.

The Office of US Trade Representative has also identified an additional US$200 billion of goods slated for a 10 per cent duty after China retaliated in an escalating trade war, and Mr Trump has said he is "ready to go" with tariffs on US$500 billion in imports - all of what China sells to the United States in a year.

This week's public hearing focuses on products from resins and chemicals to large freight containers and electric bicycles. Most of the US firms and business groups that have filed comments are seeking to have goods spared from duties on grounds that the tariffs are ultimately a tax on consumers and hamstrings them with their global supply chains.

Kimball Electronics said it may be forced to move manufacturing outside of the US to avoid Mr Trump's tariffs on diodes and electric integrated circuits.

"I do not exaggerate when I say that 25 per cent duties on these products would kill domestic durable electronics manufacturing," said the firm's chairman and chief executive Donald Charron.

Mr Trump authorised the tariffs after a probe he ordered found that China was violating intellectual property rules and forcing US firms to transfer their technology. China has denied that in its written testimony and said the tariffs "will lead to nothing but confrontation between the two countries".