A UN drugs body moved Thursday to crack down on the production of chemicals made to use illicit fentanyl, a powerful synthetic opioid killing thousands in the United States.
Fentanyl is a potent prescription painkiller which is extremely addictive, leading people to seek out illegal copycat versions. Pop star Prince died from a Fentanyl overdose last year.
According to the US Centers for Disease Control and Prevention, more than 33,000 people in America alone died from overdoses involving prescription or illicit opioids in 2015.
Deaths have also been recorded in Canada, Europe, Australia and North Africa.
Thursday's move saw the UN's Commission on Narcotic Drugs add two of the most common chemicals used by criminals to produce illicit fentanyl to its list of controlled substances.
This will require countries to regulate their production, sale and export. It also unifies action, replacing a patchwork of different local approaches to tackling the problem.
The US mission to international organisations in Vienna welcomed the commission's decision, saying it will make it "considerably more difficult for drug traffickers to access" the substances.