The United States and China will hold formal high-level talks in Beijing next week aimed at limiting the flow of fentanyl into the U.S., senior Chinese officials tell NBC News, resuming counternarcotics cooperation that was suspended for more than a year even as America struggles with what has been called its worst drug crisis in history.

China — which U.S. officials say is the primary source of the precursor chemicals synthetized into fentanyl by drug cartels in Mexico — has promised greater cooperation with the U.S. on combating the crisis. It also continues to deflect blame for it.

“I believe through this collaboration, both countries can enhance their law enforcement capabilities,” Yu Haibin, one of China’s top narcotics control officials, said in an exclusive interview this week. “We will achieve remarkable results in combating fentanyl substances, including precursors.”

But he also repeated China’s argument that America’s fentanyl problem stems from the public’s unrelenting demand for it.