China is not fighting hard enough to stop the production of fentanyl, the US ambassador to Beijing said on Wednesday, adding that he will continue to press the problem of this synthetic opioid, which is responsible for thousands of deaths in the US every year.

“We strongly urge the Chinese government to use its great power to prevent Chinese companies from selling fentanyl on the black market,” said Nicholas Burns, speaking via video link during an event in Washington.

“Frankly, we have not seen progress on this file,” he added at the US Global Leadership Coalition event, attended by companies, NGOs and officials.

China banned exports of fentanyl to the US in 2019, a move welcomed by then-Donald Trump’s administration, but shipments of chemical components needed to make the synthetic opioid to Mexico and Central America continue, experts say.

“We will not stop raising the issue and we hope the Chinese government will do the right thing,” insisted Mr Burns.

The US ambassador made these comments while the head of US diplomacy, Anthony Blinken, is expected to visit Beijing in the near future, as part of the two powers’ effort to de-escalate tensions between them, after the cancellation of his planned visit to China on February.

China has previously denied any responsibility for the fentanyl crisis, placing the blame on American society and American pharmaceutical companies.

In 2021, US opioid overdose deaths jumped from 2020 to 81,000 from 69,000 (+17%).

Washington recently imposed sanctions on Chinese companies it says are involved in the trafficking of fentanyl, a substance 50 times stronger than heroin.