The duo were among a 37-man squad for the three-day training camp in Teddington, Middlesex, which was due to finish on Monday.
Tuilagi's inclusion had caused quite a stir in rugby circles, with the Leicester centre having not played for his country since March 2016 due to injuries.
However, his international career could now be over after several newspapers reported that Tuilagi and Solomona, who made his first appearance for England during the recent tour of Argentina, went out on Sunday evening and drank alcohol, contravening the team's cultural standards.
No decisions have been made as to what will happen to them after the get-together and the RFU said it would not be making any further comment.
Tuilagi has made one appearance under England head coach Eddie Jones, in the 2016 Six Nations Championship, and last started an international in June 2014.