Reporting by CBS News' Andres Triay

Two lawyers working for special counsel Robert Mueller's office have departed, the office confirmed to CBS News.

Lawyers Ryan Dickey and Brian Richardson left the special counsel's office recently, leaving the team with 15 attorneys. CNN first reported the departures. It is unclear where they went after departing the special counsel's office.

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Mueller is investigating Russian election meddling and any ties to Trump associates.

Mr. Trump and his allies have been intensely critical of Mueller's investigation. The president has called on Attorney General Jeff Sessions to end the investigation "right now," and although he says he thinks Sessions' job is safe until the midterm elections, the president has not made any guarantee past then. Mr. Trump frequently calls the probe a "witch hunt."

Multiple people associated with Mr. Trump's presidential campaign have either been found or pleaded guilty to federal crimes as a result of Mueller's investigation.

Mueller's office has given no timeline for concluding the investigation.

— CBS News' Kathryn Watson contributed to this report