Court in northern Hebei province described the case as the first successful joint inquiry tied to fentanyl smuggling.

China on Thursday jailed nine people, one with a suspended death sentence, for illegally selling fentanyl to US buyers, the result of a landmark joint investigation over a drug that has killed thousands of Americans.

The United States has long accused China of being the main source of the deadly opioid, with President Donald Trump charging in August that Beijing had reneged on its promise to crack down on the drug.

Fentanyl is a synthetic opioid that US authorities blame for more than 100 deaths a day in the US.

The court in northern Hebei province described the case as the first successful joint investigation related to fentanyl smuggling.

China’s narcotics bureau discovered in 2017 a criminal ring based in Shanghai and eastern Jiangsu province and seized 11.9 kilogrammes (26.2 pounds) of fentanyl, acting on a tip-off from US border authorities, according to the court.

Of the nine people jailed in Hebei, one was given a death sentence with a two-year reprieve while two others received life terms for trafficking fentanyl and alprazolam – the hugely popular prescription anxiety drug branded as Xanax.

All three were “lured by high profit and huge demand” from US buyers, the Xingtai Intermediate People’s Court said.

The sentencing comes amid ongoing negotiations over a potential US-China deal after more than a year of trade conflict between the two countries, of which fentanyl has been a sticking point.

Trade war

The drug had previously often slipped past law enforcement due in part to the ability of drug makers to tweak formulas and create fentanyl analogues not restricted by existing Chinese law.

China in May began designating all fentanyl analogues as controlled substances in an effort to prevent this.

Nevertheless, Trump announced new tariffs on China over the summer as a response to what he saw as China’s continued failure to stem the flow of fentanyl into the US.

The two countries have since pledged to work together to fight the proliferation of the drug, although Beijing has rejected responsibility for the US addiction crisis.

The White House’s “drug czar”, Jim Carroll, said after meetings with Chinese officials in September that the two countries had pledged “full cooperation” against fentanyl, and he was convinced that Beijing was committed to going after traffickers.

In October, three Chinese citizens were charged by US authorities with distributing the drug in the United States.