Xingtai, China CNN  — 

Nine members of a cross-border fentanyl smuggling ring were sentenced at a public hearing in a Chinese courtroom Thursday, a rare display by Beijing of its efforts to crack down on the highly-addictive drug.

China has faced intense criticism from policy makers within the United States in recent years over accusations it has failed to prevent the synthetic opioid from flowing into the US, leading to increased friction between the two nations.

Fentanyl is an extremely potent synthetic opioid, 60 times stronger than heroin, which was responsible for close to 30,000 of the 72,000 overdose deaths in the US in 2017, according to the National Institute on Drug Abuse.

Thursday’s sentencing was presented as the culmination of the first case China and the US had worked on together that led to a successful conviction.

It comes as the two countries attempt to sign a “phase one” trade deal, a potential step towards bringing an end to their year-long trade war.

The defendants in Thursday's court case in Hebei, who were accused of being part of a fentanyl smuggling ring.

The sentencing took place in the city of Xingtai in the northern province of Hebei. The ringleader, a 41-year-old man, was given a suspended death sentence for selling and manufacturing narcotics and two others received life sentences.

The remaining six members of the smuggling ring were given sentences varying from six months to 10 years. During their arrests, police seized 26 pounds (11.9 kilograms) of fentanyl and 42 pounds (19.1 kilograms) of alprazolam.

“The successful sentencing, especially the heavy sentencing of the principal criminals, fully demonstrates the Chinese government’s firm stance and determination to severely punish fentanyl-related crimes,” Yu Haibin, deputy head of China’s National Narcotics Control Commission, the country’s top drug law enforcement agency, said at a press conference after the hearing.

In a statement Thursday, White House Office of National Drug Control Policy Director Jim Carroll said the sentencing was a “direct result” of pressure by the US and President Donald Trump.

“China’s fentanyl trafficking and production prosecution is a positive step in following through on the pledge secured by President Trump. We look forward to further cooperation to stop the flow of these deadly substances into the United States,” he said.

Yu Haibin (L), deputy director of China National Narcotics Control Commission shakes hands with Austin Moore, US Department of Homeland Security and Immigration and Customs Enforcement attache to China, on November 7.

A nickname and a phone number

Thursday’s case began with a tip off from the US authorities in August 2017 involving only a nickname and a single phone number.

After three months of investigation, Chinese narcotics authorities busted the drug ring in a series of raids across the country, including in Hebei and Jiangsu provinces.

Yu said that after the fentanyl was manufactured in China, it was sent overseas in postal packages.

Despite their cooperation on this case, both China and the US have been critical of each others’ work in tackling the fentanyl crisis.

Two guards stand outside the Xingtai Intermediate People's Court in Hebei Province on Thursday November 7.

A November 2018 report by the US-China Economic and Security Review Commission under the US Congress said that China was still “the largest source of illicit fentanyl” in the US, although it did not provide figures to back up the claim.

In a statement released in August, the US Office of National Drug Control Policy claimed that China “continues to pour poison into our communities.”

But the Chinese government has repeatedly insisted it is fulfilling its promises to the US and international obligations. In May, Beijing made all fentanyl derivative products “controlled substances” that had been part of an agreement between Trump and Chinese President Xi Jinping in December 2018.

At his press conference, Yu said that it was impossible for China to still be the main source of fentanyl in the US given efforts by Beijing to end the supply.

He added that since 2012 the US had only shared six leads with Chinese authorities, three of which Yu claimed had led to joint investigations.

The decision by Chinese authorities to hold Thursday’s high-profile public sentencing while trade negotiations are ongoing is likely to be seen as an attempt to curry favor with the US.

Stopping the flow of the deadly drug into the US has been an important part of Trump’s policy agenda. He has placed the blame squarely at China’s door and often links the fentanyl epidemic and trade talks.

In a tweet in August, Trump blamed Xi for the fentanyl crisis and announced that all deliveries of the drug from China would be searched and possibly refused.

Speaking on Thursday, Yu strongly denied that the sentencing was linked to the trade talks. “Drug cases are about saving lives, and they shouldn’t be linked to trade or any other issues. Nothing is more important than human lives,” he said.

CNN’s Yong Xiong contributed to this article.