Washington: US Special Counsel Robert Mueller warned that Russian intelligence services have active "interference operations" in the US and asked a judge to limit the pretrial evidence provided to a Russian firm indicted over meddling in the 2016 election.

Mueller asked a federal judge in Washington for an order that would protect the handover of voluminous evidence to lawyers for Concord Management and Consulting LLC, one of three companies and 13 Russian nationals charged in a February indictment. They are accused of producing propaganda, posing as US activists and posting political content on social media as so-called trolls to encourage strife in the US.

Special counsel Robert Mueller Credit:AP

The threat of public or unauthorised disclosure of evidence would help foreign intelligence services, particularly in Russia, in "future operations against the United States," Mueller's prosecutors wrote in a filing on Tuesday.

"The substance of the government's evidence identifies uncharged individuals and entities that the government believes are continuing to engage in interference operations like those charged in the present indictment," prosecutors wrote.