Facebook/Maria Butina

A 29-year-old gun-rights activist served as a covert Russian agent while living in Washington, gathering intelligence on American officials and political organizations and working to establish back-channel lines of communications for the Kremlin, federal prosecutors charged Monday.

The announcement of the arrest of Maria Butina came just hours after US President Donald Trump met with Russian President Vladimir Putin and just days after special counsel Robert Mueller charged 12 Russian intelligence officials with directing a sprawling hacking effort aimed at swaying the 2016 election.

Mueller didn't file the charge against Butina, but court papers show her activities revolved around American politics during the 2016 campaign and included efforts to use contacts with the National Rifle Association to develop relationships with US politicians and gather intelligence for Russia.

Court papers also reveal that an unnamed American who worked with Butina claimed to have been involved in setting up a "private line of communication" ahead of the 2016 election between the Kremlin and "key" officials in an American political party through the NRA.

The court papers do not name the political party mentioned in the October 2016 message, but they contain details that appear to refer to the Republican Party. The documents don't say whether the back channel was ever established.