On August 20, President Trump blamed China for supplying the synthetic opioid fentanyl that’s devastating U.S. communities. In a strongly-worded tweet, Trump accused China of moving the drug through the U.S. Postal System. The tweet marks the second time Trump has accused China of playing a role in the U.S.’s ongoing opioid crisis, and China’s Drug Control Agency’s rejection of those claims marks the second time they’ve disputed them. Evidence to support Trump’s claims has not been provided, Beijing officials say. This back-and-forth is once again heightening the already-tense relations between the two nations.

China Again Denies “Flooding” the U.S. with Fentanyl

Prior to his November 2017 visit to China, President Trump claimed that China was the producer of most of the synthetic opioid fentanyl coming into the United States. He also stated that he would discuss the issue with President Xi Jinping at their Beijing meeting. And just days ahead of the visit, Chinese officials rejected Trump’s claim.

Wei Xiaojun, deputy director general of the Narcotics Control Bureau of the Ministry of Public Security, acknowledged that in some individual cases, fentanyl manufactured illicitly in China had ended up in the United States. But Wei expressly denied the claim that most U.S. fentanyl comes from China.

Nevertheless, both the US Drug Enforcement Administration and the White House Office of National Drug Control Policy consider China to be North America’s main source of fentanyl and related drugs. Trump’s latest allegations to that effect came ahead of a meeting last Thursday with Attorney General Jeff Sessions. Sources inside the meeting say Trump reiterated his calls for convicted opioid dealers to receive the death penalty. The meeting also discussed delaying potential prison and sentencing reforms until after the midterm elections.

Senior Chinese Officials Call Trump Tweet “Highly Irresponsible”

Senior officials with China’s National Narcotics Control Commission found similar language to denounce Trump’s tweet claiming it was “outrageous” that fentanyl continued “pouring into” the U.S. Yu Haibin responded to Trump in a press briefing today, referring to Trump’s comments as “unacceptable” and “irresponsible,” CNN reports.

It is outrageous that Poisonous Synthetic Heroin Fentanyl comes pouring into the U.S. Postal System from China. We can, and must, END THIS NOW! The Senate should pass the STOP ACT – and firmly STOP this poison from killing our children and destroying our country. No more delay! — Donald J. Trump (@realDonaldTrump) August 20, 2018

In November, officials in China were willing to concede that some illicitly-made fentanyl had made it to the United States. This time, however, Yu said “it’s highly irresponsible to draw such a conclusion based on some individual cases,” according to CNN. Yu reiterated that neither the U.S. government or its law enforcement agencies have supplied proof that most fentanyl comes from China.

But the Trump administration remains convinced China is the source. In 2017, a Congressional report cited a handful of law enforcement cases and drug investigators who had traced fentanyl linked to overdose deaths to manufacturers in China. This report appears to be what’s behind Trump’s allegations.

At the briefing, other Beijing officials announced the addition of 32 new drugs to China’s list of prohibited controlled substances. The list includes fentanyl and its analogs, including several other “designer” narcotics. Authorities also emphasized that China had installed 13,000 security checkpoints at shipping companies in an effort to address the U.S.’s drug trafficking concerns.