China announced on Monday that it would treat all variants of the powerful opioid fentanyl as controlled substances, making good on a pledge the country’s leader, president Xi Jinping, made to US president Donald Trump late last year.

China’s export of the drug, a family of synthetic opioids blamed for thousands of overdoses in the United States, has long been a source of tension in relations and has, more recently, become tangled up in the continuing trade war.

China already treats more than two dozen variants of fentanyl and its precursors as controlled substances, thus strictly regulating their production and distribution, but it has banned those variants only after reviewing them case by case, a process that can be lengthy.

The latest step would expand restrictions to all “fentanyl-related substances”, effective May 1st. That could plug gaps that, experts and US officials have said, allowed manufacturers in China to make novel variations of the drug that were not technically illegal.

In December, Mr Trump announced a promise that Mr Xi made to him at the Group of 20 meeting in Buenos Aires, Argentina, saying then that the step formalised on Monday could be a “game changer”. He had previously taken to Twitter earlier to excoriate China over the issue, accusing it of “killing our children and destroying our country”.

Officials from three Chinese agencies, including the ministry of public security, announced the change at a news conference that included representatives from foreign embassies, including the US embassy. As before, however, the officials denied that China was causing the scourge of fentanyl-related deaths in the United States, saying the blame lay there.

Lacking evidence

Liu Yuejin, vice-commissioner of the National Narcotics Control Commission, said accusations by US officials lacked evidence and China co-operated closely with the United States on cases of illegal trafficking, which was “extremely limited”.

“We believe that the United States is the main cause of the problem of the abuse of fentanyl in the United States,” he said, citing weak enforcement and a culture of addiction.

Weak regulation over China’s sprawling chemical industry has raised the possibility that a new ban to cover all forms of fentanyl might not be entirely effective. Mr Liu, however, promised that China would strictly enforce the new rules, as officials have insisted they have thus far. – New York Times