(PHOENIX) — The attorney general of Arizona issued a warning letter to a megachurch that claims its air filtration system “kills 99 percent of COVID within 10 minutes.”

Attorney General Mark Brnovich sent the letter to Phoenix’s Dream City Church on Thursday, saying that their claim — which Brnovich said was not backed by any science — may be illegal.

“In the absence of scientific evidence regarding COVID-19 specifically, statements suggesting that a product could provide nearly guaranteed protection from COVID-19 infections create a misrepresentation or a false promise. Misrepresentations and false promises are illegal under A.R.S. § 44-1522,” Brnovich wrote.

The church, which can seat 3,000 people, had also claimed “when you come into [the church’s] auditorium, 99 percent of COVID is gone” and “you can know when you come down here, you’ll be safe and protected,” according to his letter.

Dream City Church, which has six other locations, made some of the claims in a Facebook video ahead of hosting President Donald Trump this week. The video has since been removed.

Dream City Church did not immediately respond to ABC News for comment. However, before the warning letter was sent, they issued a statement saying they used the words COVID and coronavirus interchangeably.

“Our statement regarding the CleanAir EXP units used the word COVID when we should have said Coronavirus or COVID surrogates,” the church said. COVID-19 is the disease caused by the coronavirus, of which there is more than one.

The church’s air filtration system was purchased from Clear Air EXP, Brnovich said.

Brnovich sent a cease-and-desist letter to Clean Air EXP the same day, demanding the company stop advertising air purification systems with suggestions the systems neutralize COVID-19.

He said that the company has and continues to advertise that its air filtration products eliminate 99.9% of “airborne coronavirus surrogates.”

In a statement posted on the Clear Air Exp website, the company reiterated that claim.

“Our coronavirus surrogate testing results are significant for the future of clean air,” the company claimed.

Brnovich said the message is not based on scientific research or public health authority certification, and that the message implies Clean Air EXP’s products can prevent the virus’ transmission and infection.

An expert who spoke to ABC News said the public should be skeptical of any technology that claims to eliminate all airborne viruses and especially COVID-19.

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