Russian President Vladmir Putin demanded that US investigators produce evidence that Russians interfered in the last US presidential elections.

“We [Russia] cannot respond to the accusations if the accused have not violated Russian laws,” Putin said in an interview with NBC News’ Megyn Kelly on Friday. “I need to see what these people have done. Give us the documents, the relevant information.”

Putin’s statement comes one month after US Special Counsel Robert Mueller charged 13 Russians and three firms with interfering in the 2016 presidential vote as part of what it called a conspiracy to support Donald Trump and disparage Hillary Clinton.

“With all due respect for you personally, with all due respect for Congress, you must have people with legal degrees, 100 percent you do,” Putin said to Kelly.

He said U.S. authorities should send Russia’s general prosecutor an official request.

“This has to go through official channels, not through the press or yelling and hollering in the United States Congress,” Putin said.