China and the United States will strengthen intelligence sharing and joint investigations to curb fentanyl-related drug crimes, a senior police official said on Nov 3.

Wei Xiaojun, deputy director of the narcotics control bureau of the Ministry of Public Security, also said that China plans to list two new fentanyl precursor chemicals－4-ANPP and NPP－as controlled substances. Twenty-three related compounds are already on the controlled list.

Fentanyl is among a group of new, powerful painkillers collectively known as “novel psychoactive substances” that are either opioids or act like them, and can be 50 to 100 times more potent than morphine. The US Centers for Disease Control said fentanyl resulted in about 20,000 deaths in the country last year.

Wei said that Chinese authorities and US police departments are in contact on some fentanyl trafficking cases and have set up joint investigative teams.

“We’re actively sharing intelligence and exchanging information with our US counterparts. Once we have solid evidence, we’ll carry out joint actions,” he said.

Lance Ho, a senior US narcotics control official, said on Nov 3 that China and the US have made progress in countering cross-border drug-related crimes.

“The two sides will further enhance information exchanges and conduct joint actions to effectively curb such crimes,” he said.

Last week, two Chinese men were charged by US authorities with producing and trafficking fentanyl. The two suspects－Zhang Jian and Yan Xiaobing－were accused of operating labs that produced fentanyl and other drugs in China, using the internet to find buyers and smuggling the drugs to the US via international parcels or express services.

The two are currently in China, and US authorities have asked for China’s assistance in probing the case, and requested that it send the pair to the US to face trial, according to a report in USA Today.

Wei said China has attached great importance to such cases.

“Some of the fentanyl in the US market comes from China, but there is no proof that most of it is from China,” he said.

As for the extradition request from the US, Wei said the Chinese side will take action based on the facts of the case and in accordance with Chinese laws, and has asked the US to provide more solid evidence.

He said it was “regrettable” that the US decided to announce the case unilaterally because it might affect China’s ongoing investigations.