Chinese Ambassador to the United States Cui Tiankai on Sunday, Feb. 9, slammed Sen. Tom Cotton’s (R-Ark.) comment suggesting the coronavirus could have come from China’s biological warfare program as a “crazy” thing.

“I think it’s true that a lot is still unknown and our scientists, Chinese scientists, American scientists, scientists of other countries, are doing their best to learn more about the virus, but it’s very harmful, it’s very dangerous, to stir up suspicion, rumors, and spread them among the people,” Cui said.

Cui said that any speculation would “create panic” and could also provoke xenophobia and racist discrimination. 

“There are all kinds of speculation and rumors,” he continued, noting that there were also conspiracy theories about the virus originating from some military labs in the United States. “How can we believe all these crazy things?”

Earlier this month, Cotton said that Chinese officials misled the public on the origins of the novel coronavirus, saying that Beijing was “lying about it from the very beginning” to downplay the seriousness of the epidemic. He also suggested that the virus may have originated in a “superlaboratory” in Wuhan, where the outbreak began. 

Several reports emerged in recent weeks suggesting that the Chinese government has lowered the number of infections and casualties from the coronavirus.

Cotton, who described the coronavirus as the “biggest and most important story in the world” and “worse than Chernobyl” on Sunday took to Twitter to defend his comments.

“Fact: super-lab is just a few miles from that market[.] Where did it start? We don’t know. But burden of proof is on you & fellow communists. Open up now to competent international scientists,” Cotton added in a subsequent post.

Cui also defended the way that the Chinese government had handled the case of Li Wenliang, the Chinese doctor who got trouble with police when trying to give an early alarm of the virus. He died Friday after succumbing to the disease himself.

“He was a doctor, and a doctor could be alarmed by some individual cases, but as for the government, you have to base your decisions on more solid evidence and signs,” Cui said. “We are all very saddened about the death of Dr. Li. He was a good doctor … I don’t know who tried to silence him, but there was certainly disagreement or people were not able to reach agreement on what exactly the virus is, how it is affecting people.”

When asked about a citizen journalist, Chen Qiushi, who covered the outbreak of virus epicenter Wuhan and has disappeared, Cui responded “I have never heard of this guy, so I don’t have any information to share with you.”