A U.S. federal grand jury has approved the first charges in an investigation of Russian influence on U.S. elections, a probe led by special counsel Robert Mueller.
A report late Friday from CNN quoted sources as saying anyone who is charged could be taken into custody as soon as Monday. The exact charges are unclear.
A spokesman for Mueller's office declined CNN's request for comment.
CNN said lawyers working on Mueller's team were seen entering the federal courtroom in Washington, D.C., on Friday, where the grand jury meets to hear testimony.
Mueller has kept a tight lid on information about the probe.
Mueller was appointed special counsel in May, shortly after the firing of then-FBI director James Comey, to look into allegations that the Trump campaign may have colluded with Russia to win the election. He is also examining the possibility that the president may have tried to interfere with the Russia investigation.
The probe is also examining possible financial ties between Russian businesses and members of the Trump campaign, and foreign lobbying conducted by former Trump campaign chairman Paul Manafort and former national security adviser Michael Flynn.
In addition to Mueller's probe, three congressional committees are conducting their own investigations into possible Russian influence on the election.