The United States is facing an epidemic of deaths caused by fentanyl, a synthetic opioid 50 times more potent than heroin and much easier and cheaper to produce.

Washington has long accused Beijing of failing to crack down on the production of chemical components that are typically exported to Mexico and made into fentanyl before being transported into the US.

Trump this week threatened to slap a further 10 percent tariff on Chinese imports, saying not enough was being done to stem the flow of drugs into the US.

Asked about the prospective tariffs on Thursday, a spokesman for China's commerce ministry said that the country's "position of opposing the unilateral imposition of tariffs is consistent".

"Imposing tariffs at will on trading partners will not solve the United States' own problems," spokesman He Yadong said at a press conference.

"The United States should abide by WTO rules and work with China in accordance with the principles of mutual respect, peaceful coexistence and win-win cooperation to jointly promote the stable and sustainable development of China-US economic and trade relations," said He.

The US and China revived drug control talks after a summit between incumbent President Joe Biden and his Chinese counterpart Xi Jinping in San Francisco last November.

This summer, a counternarcotics working group convened in Washington and China, announcing it would step up its regulation of three key fentanyl precursors, though the prospects of success remain unclear.

Trump has vowed to take a tougher line on China than Biden, raising the spectre of another trade war that hit billions of dollars in commerce between the two superpowers during his first term as president.

China has consistently opposed what it calls unlawful, unilateral measures designed to contain its rise, though Xi told Biden at a summit this month that Beijing was willing to work with the next US administration.

Trump also said this week that he would impose tariffs of 25 percent on US neighbours Canada and Mexico for their perceived roles in the fentanyl crisis.