U.S. prosecutors have accused Russian operatives of seeking to interfere with a federal agency charged with policing American elections, as part of their case relating to interference in the 2016 U.S. presidential contest, saying the group aimed to interfere with a ban on some election spending by foreign nationals.

In a court document released on Tuesday, federal prosecutors said they would ask a U.S. grand jury to issue a superseding indictment, alleging the Russia-based Internet Research Agency conspired "to interfere with more than one lawful function of the Federal Election Commission."

The prosecutors would not seek to add charges or expand the conspiracy, they wrote in the filing submitted to the U.S. District Court for the District of Columbia as part of the case, which is among those that have stemmed from U.S. special counsel Robert Mueller's investigation into Russian interference in the 2016 U.S. election.