MEXICO CITY (AP) — Mexico’s president asked his Chinese counterpart for help Tuesday in halting chemicals from China used by Mexican drug dealers to illegally produce fentanyl, while also complaining of “rude” US pressure to curb the drug trade.

President Andrés Manuel López Obrador has previously said that fentanyl is America’s problem and is caused by “a lack of hugs” in US families. On Tuesday he doubled down on those themes, but went further, venting in a letter to Chinese President Xi Jinping about “rude threats” from US legislators over the drug trade.

López Obrador complained about calls in the United States to designate Mexican drug gangs as terrorist organisations. Some Republicans have said they favour using the US military to crack down on the Mexican cartels.

“Unjustly, they are blaming us for problems that in large measure have to do with their loss of values, their welfare crisis,” López Obrador wrote to Xi in the letter published Tuesday. “These positions are in themselves a lack of respect and a threat to our sovereignty, and moreover they are based on an absurd, manipulative, propagandistic and demagogic attitude.”

Only after several paragraphs of venting, López Obrador brings up China’s exports of fentanyl precursors, and asked him to help stop shipments of chemicals that Mexican cartels import from China.

“I write to you, President Xi Jinping, not to ask your help on these rude threats, but to ask you for humanitarian reasons to help us by controlling the shipments of fentanyl,” the Mexican president wrote.

China has taken some steps to limit fentanyl exports, but mislabeled or harder-to-detect precursor chemicals continue to pour out of Chinese factories.

It was not immediately clear if Xi had received the letter or if he had responded to it. López Obrador has a history of writing confrontational letters to world leaders without getting a response.

López Obrador has angrily denied that fentanyl is produced in Mexico. However, his own administration has acknowledged finding dozens of labs where it is produced, mainly in the northern state of Sinaloa.

Most illegal fentanyl is pressed by Mexican cartels into counterfeit pills made to look like other medications like Xanax, oxycodone or Percocet, or mixed into other drugs, including heroin and cocaine. Many people who die of overdoses in the United States do not know they are taking fentanyl.

Over the last week, López Obrador has fixated on press reports stating that the National Basketball Association had offered in talks with the players’ union to stop testing or penalising players for using marijuana.

The Mexican president took that as evidence of US social and moral decay, even though Mexico has legalised the growing of marijuana for personal and medical use.