An arrest is believed to be imminent in the investigation into Russian meddling in the US election.

A Washington, DC grand jury has approved the first charges in the investigation led by Robert Mueller into the potential Russian meddling in the 2016 presidential election.

It's not clear how serious the charges are, but CNN is reporting that the secrecy around them suggests several people are likely to be accused.

Sources told CNN the charges will be filed on Monday and anyone charged can be arrested that same day.

Mueller was appointed in May to investigate whether the Trump campaign had colluded with the Russian government during the election.

It is unclear what the charges are but it will all be revealed on Monday.

The investigation has also been looking into whether Donald Trump obstructed justice when he allegedly asked former FBI director James Comey to drop an inquiry into Michael Flynn.

Flynn was fired from the administration in February after it was found that he had misled vice president Mike Pence on his dealings with Russian officials.