WASHINGTON (Reuters) - U.S. President Joe Biden on Thursday said the idea of sanctioning Russian President Vladimir Putin personally over Russia's invasion of Ukraine remained a possibility.

       "It's not a bluff, it's on the table," Biden told reporters at the White House. He did not reply to a question about why such personal sanctions targeting Putin were not included in a coordinated set of sanctions announced on Thursday.

       (Reporting by Steve Holland, writing by Andrea Shalal; editing by Chris Reese)