China has made relentless efforts and gained significant achievements in its combat against fentanyl and other illicit drugs, and it's groundless for the United States to use the fentanyl issue to justify tariff hikes, officials and experts said.

China has some of the strictest and most thoroughly implemented drug control policies in the world, a spokesperson for the Ministry of Public Security said, adding that China, also a state party to three United Nations drug control conventions, has cooperated actively with the US and other countries to tackle illicit drugs.

The spokesperson made the remarks after the US announced its decision to levy a 10 percent additional tariff on imports from China, citing the fentanyl issue as a reason.

Voicing strong dissatisfaction and firm opposition to the reasoning, the spokesperson said in a statement on Sunday that China has conducted extensive and pragmatic drug-control cooperation with the US in recent years.

Both sides have seen progress in substance scheduling, intelligence exchange, the cracking of specific cases and other fields, the spokesperson said, taking note of China's scheduling the entire class of fentanyl-related substances in 2019.

Requested by the US, the scheduling was a goodwill gesture that was made even though there was no large-scale abuse of fentanyl-related substances in China, the spokesperson said.

The move made China the first country in the world to schedule the entire class of the substances.

Li Wenjun, a professor of People's Public Security University of China, said by scheduling the entire class, China has placed under strict control the production, sales and use of fentanyl-related substances.

The scheduling has effectively targeted a variety of "designer drugs", synthetic drugs with slightly modified chemical structures which are invented to escape regulation, Li said.

Since the scheduling, China has not received reports from the US about seizures of fentanyl-related substances originating from China, the spokesperson of the Ministry of Public Security said. The US, in contrast, hasn't created a permanent schedule of the entire class of the substances, the spokesperson said.

China and the US stepped up their collaboration to combat illicit drugs last year, which saw a series of meetings between both sides.

In November last year, delegations from the two countries attended the 10th Bilateral Drug Intelligence Working Group Meeting in Shanghai.

During the meeting, they had in-depth exchanges and agreed to strengthen dialogue and communication on the basis of mutual respect, management of differences and mutually beneficial cooperation, according to the Office of China National Narcotics Control Commission.

In January 2024, the two countries launched the China-US Counternarcotics Working Group, which had its first senior officials' meeting six months later in Washington.

China has also strengthened its regulation of illicit drugs over the past year. It added as many as 46 substances into its controlled drug list in July, and regulated seven chemicals in September.

China ranks among the best countries in the world in its response to drug-related crimes, but the issue of fentanyl abuse in the US cannot be resolved by only relying on China improving its own drug regulation policies, said Li.

Wang Ruiyuan, an associate professor of Criminal Investigation Police University of China, said the root of the US' fentanyl crisis lies in its long-term drug abuse issue.

Wang, a researcher in anti-drug studies, said China, which has not seen large-scale abuse of fentanyl, has shown great sincerity in its cooperation with the US to address the fentanyl crisis.

The US, on the other hand, is politicizing the drug issue and using it as a "chip" to serve its tariff policies, Wang said, adding that the move will hurt the foundation of its counternarcotics cooperation with China.

The issue of illicit drugs, including fentanyl, is a challenge for all humanity that requires collaboration among different countries, Wang said, adding that one will only hamper such collaboration by blaming others for its own problems.