Iran’s supreme leader on Sunday cited a conspiracy theory claiming America bio-engineered the coronavirus. Citing this theory, Ayatollah Ali Khamenei refused U.S. help in fighting the virus.

Khamenei not only repeated the conspiracy theory, which is being peddled by Chinese authorities in order to take the blame off of the communist country for the outbreak, but claimed the virus was created using Iranian genetic data to specifically target Iran, The Associated Press reported.

“I do not know how real this accusation is but when it exists, who in their right mind would trust you to bring them medication?” Khamenei said, as reported by the AP. “Possibly your medicine is a way to spread the virus more.”

He then claimed that the coronavirus “is specifically built for Iran using the genetic data of Iranians which they have obtained through different means.” As the AP noted, there is no evidence to support this accusation.

“You might send people as doctors and therapists, maybe they would want to come here and see the effect of the poison they have produced in person,” Khamenei added.

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There is no scientific proof offered anywhere in the world to support Khamenei’s claims. However, his comments come after Chinese government spokesman Lijian Zhao tweeted earlier this month that it “might be US army who brought the epidemic to Wuhan. Be transparent! Make public your data! US owe(s) us an explanation!” Lijian likewise offered no evidence to support his claim, which saw the U.S. State Department summon China’s ambassador to complain. A Chinese state newspaper tweeted Sunday another allegation trying to link the virus to Italy, similarly hard-hit by the outbreak. Wuhan is the Chinese city where the first cases of the disease were detected in December.

Khomenei made his unsubstantiated claims on Sunday in a speech that was televised live across Iran. Sunday is Nowruz, the Persian New Year. Khomenei made the remarks during a broadcast marking the event and the Islamic commemoration Isra and Miraj.

“His comments come as Iran has over 21,600 confirmed cases of the new coronavirus amid 1,685 reported deaths, according to government figures released Sunday. Experts still fear Iran may be underreporting its cases,” the AP reported. “Iran is one of the hardest-hit countries in the world by the new virus, sweeping across leaders in both its civilian government and Shiite theocracy. Across the Mideast, Iran represents eight of 10 cases of the virus and those leaving the Islamic Republic have carried the virus to other countries.”

The U.S. has offered aid to Iran to help stop the coronavirus, but the country has refused the help, claiming America was being disingenuous in its attempts at the country struggles with U.S. sanctions.

The AP also reported that this isn’t the first time Iranian leaders have chosen to believe conspiracy theories that make the U.S. look bad.

“Iranian hard-liners have supported conspiracy theories in the past when it suited their interests. Following the Sept. 11 attacks, some publicly doubted al-Qaida’s role and state TV promoting the unfounded conspiracy theory that the Americans blew up the building themselves,” the AP reported.

“Former hard-line President Mahmoud Ahmadinejad similarly raised doubt about the Sept. 11 attack, calling it a ‘big lie,’ while also describing the Holocaust as a ‘myth.’”