Beijing(CNN) A top official in China's drug control agency has hit back at accusations that Chinese suppliers are fueling the ongoing opioid crisis in the United States, arguing that Washington should pay more attention to domestic factors before pointing fingers at others.
"It's common knowledge that most new psychoactive substances (NPS) have been designed in laboratories in the United States and Europe, and their deep-processing and consumption also mostly take place there," said Liu Yuejin, deputy chief of China's National Narcotics Control Commission, during a press conference Monday.
"The US should adopt a comprehensive and balanced strategy to reduce and suppress the huge demand in the country for fentanyl and other similar drugs as soon as possible," said Liu, whose comments coincided with the release of China's annual drug situation report.
"When fewer and fewer Americans use fentanyl, there would be no market for it."
NPS include such "designer drugs" as fentanyl, a cheap synthetic opioid at least 50 times stronger than heroin that has been flooding the US.
US President Donald Trump last October declared the opioid crisis a national public health emergency and promised to end the epidemic.
A 2017 congressional report labeled China as the primary source of fentanyl in the US, citing law enforcement and drug investigators.
Responding to a CNN question on China's plans to further curb the sale and shipment of fentanyl products to the US, Liu gave a laundry list of measures that he said the US authorities should adopt, ranging from intensified drug-prevention campaigns to better treatment and assistance for drug users.
"The US should strengthen its crackdown on distributors, traffickers and drug-related criminal rings," he added. "It should investigate and arrest more lawbreakers."
During his state visit to China last November, Trump brought up the topic with his Chinese counterpart Xi Jinping, with the two leaders agreeing to bolster mutual cooperation on fighting narcotic crimes.
On Monday, Chinese officials stressed the "broad and effective cooperation" between the two countries.
Liu pointed to a series of cross-border trafficking cases jointly cracked by the two sides, and highlighted Beijing's latest efforts in intercepting drugs bound for the US at major ports.
He also reiterated Beijing's long-held position that China, in a "proactive and responsible" spirit, has listed 138 NPS -- including 23 fentanyl analogues -- as controlled substances even though there is no widespread abuse of these drugs within its borders.
In its annual drug report released Monday, China says the number of drug abusers in the country of 1.4 billion people rose nearly 2% in 2017 to 2.55 million, but the growth rate declined.
The use of synthetic drugs and opioids accounted for the overwhelming majority of the cases.
The report warns of fast-emerging new drugs, including those made of non-controlled chemicals, as well as the continued threats of internet-based sales and cross-border trafficking -- citing more than 1,600 arrests of overseas suspects.
In the United States, since 1999, the number of overdose deaths involving opioids has quadrupled.
From 2000 to 2015, more than half a million people died of drug overdoses, with opioids accounting for the majority of those and now killing more Americans every year than breast cancer.
Recently released figures from the US Centers for Disease Control and Prevention found that around 64,000 people died from drug overdoses in 2016.
Representatives from the US embassy -- along with diplomats from other countries -- attended Monday's press conference but did not speak.
Liu, the senior Chinese official, brushed aside suggestions that increasingly shaky China-US relations -- marked by an on-again, off-again trade war -- could impede bilateral efforts on the fentanyl issue.
"When it comes to a matter of principle such as the international cooperation on narcotics control, we won't let it be affected or disrupted by other political and economic factors," he said. "We hope other countries, including the United States, would do the same thing."