Fox Business anchor Maria Bartiromo talked to a top Trump adviser about the possibility that the coronavirus was a biological weapon developed by China.

During a conversation about the virus's effects on trade and economy, Bartiromo asked White House trade adviser Peter Navarro on Monday about the idea that the Chinese government may have manufactured the deadly virus in a "weapons lab" to target the United States.

She pointed to the end of last year, when China decided to send its top trade negotiator to Washington to sign "phase one" of a trade deal with the U.S.

“They knew that coronavirus had happened back in December," Bartiromo said. "They sent a delegation to the White House to shake everybody’s hand. They knew that they had this virus that had started with the 'phase one.' Then, they sent the largest delegation ever to Davos.”

The anchor also indicated she was unsatisfied with Cui Tiankai, China’s ambassador to the U.S., who recently dismissed rumors about the coronavirus. He rejected similar comments made by Republican Sen. Tom Cotton, who suggested the virus could have been man-made inside a laboratory in Wuhan, China.

“Do we know if this started in a research lab?" Bartiromo asked. "And how come they won’t allow the CDC in there to better understand how this started, because if they started this in a weapons lab, that’s evidence that they are developing or trying to develop weapons of mass destruction, biological weapons.”

Navarro said the "question of how this started ultimately has to be answered" but stressed that fighting the crisis was paramount.

Neither Bartiromo nor Navarro discussed evidence related to the origins of the coronavirus.

Questions have been raised about China's response to the mystery illness, which has infected more than 40,000 people globally. Chinese President Xi Jinping was spotted wearing a face mask on Monday as the coronavirus death toll eclipsed 1,000 people. The prevailing theory is that meat sold at wild animal markets in the city of Wuhan was the starting point for the coronavirus.

The Centers for Disease Control and Prevention have said the disease remains a "very low" risk for Americans.