White House COVID-19 adviser Scott Atlas apologized for his appearance in an interview for RT, a Russian government-funded network formerly known as Russia Today.

Atlas tweeted his apology explaining that he was “unaware” of RT being registered as a foreign agent and its ties to the Russian government.

RT was deemed to be a foreign agent by the U.S. Justice Department for its affiliation with the Russian state and its attempts to spread propaganda to Americans through social media platforms. Twitter, one of the platforms RT uses, banned a video from RT which the social media giant flagged as “misinformation.”

According to national intelligence officials, RT is suspected to have taken part in Russian interference with the 2016 U.S. election.

YouTube has taken similar measures and marked RT’s videos with a warning that read “partially or wholly funded by the Russian government.”

In the interview, the coronavirus adviser disagreed with lockdown and quarantine mandates and claimed that there is no need to test asymptomatic people despite the rising number of positive cases.

On Sunday, the White House responded that Atlas “did it on his own without approval by the White House.” The administration denied giving permission to Atlas to attend the interview.