Protester tosses Russian flags at President Trump in Capitol

A protester tossed Russian flags at President Donald Trump as he walked through the Capitol for a lunch with Republican senators.

The protester, who has been identified as Ryan Clayton, was standing with reporters outside the Senate chamber on the building's second floor when he threw the flags at Trump, who was walking alongside Senate Majority Leader Mitch McConnell.

Clayton was heard yelling, "Trump is treason. Why are you talking about tax cuts when you should be talking about treason?"

Clayton was taken into custody by security officers afterwards.

Fox News has learned that Clayton got into the Capitol despite being a "known entity" to U.S. Capitol security forces.

Clayton is part of a group called Americans Take Action, which is seeking Trump's impeachment. Back in July, Clayton stood among reporters in a Senate office building and threw Russian flags at Trump's son-in-law, Jared Kushner.

It is believed Clayton entered the Capitol through the House side with an expired visitor's pass. U.S. Capitol Police are trying to determine how Clayton was able to get into a restricted area of the second floor alongside the assembled reporters and photographers, according to Fox News.

Clayton is not being "especially cooperative" with authorities following his arrest, Fox News says.

"I have also been told that senior Capitol security officials here are very upset with this," said Fox News senior producer Chad Pergram. "The term that was used on me is that there is egg on their face and that this was a failure on multiple levels."

Clayton was charged with unlawful conduct.

Information from Fox News and the Associated Press used in this report.