A theory that COVID-19 could have emerged from a lab leak in Wuhan, China, where the disease was first seen towards the end of 2019, has caused tension between the U.S., China and the World Health Organization (WHO). President Joe Biden ordered U.S. intelligence agencies to conduct a 90-day review of “two likely scenarios” in late May, including the lab leak theory and another that COVID-19 potentially transferred from animals to humans.

“If they want to baselessly accuse China, they better be prepared to accept the counterattack from China,” said Fu Cong, the Chinese Foreign Ministry’s director-general.

White House Press Secretary Jen Psaki said Monday that the report is expected to go public in “several days.”

A joint WHO-CHINA report published earlier this year said a lab leak was “extremely unlikely” and that the animal to human theory was most likely. However, in late March, WHO Director-General Tedros Adhanom Ghebreyesus said “all hypotheses are on the table and warrant complete and further studies.”

For more reporting from the Associated Press, see below.

Fu accused the U.S. of politicizing the issue by seeking to blame China.

He said at a briefing for foreign journalists that “scapegoating China cannot whitewash the U.S.”

After the joint WHO-China report was released, China wants the investigation to move on to other possibilities. The most likely scenario, the report said, is that the virus jumped from bats to another animal that then infected humans.

China has responded to continuing speculation about a leak from the Wuhan Institute of Virology by suggesting the virus could have escaped from Fort Detrick, a U.S. military lab in Maryland.

Fu, who heads the Foreign Ministry’s Arms Control Department, denied that China is engaging in a disinformation campaign.

He said that if other parties insist on pursuing the lab leak theory, then the WHO team of researchers should visit Fort Detrick. He portrayed it as a fairness issue, since the WHO has been to the Wuhan institute twice.

“If Dr. Tedros believes that we should not rule out the hypothesis of a lab leak, well, he knows where to go,” Fu said. “He needs to go to the U.S. labs.”

China notes that Fort Detrick’s infectious disease institute has studied coronaviruses and that it was closed for several months in 2019-20 for safety violations.