"The president's schedule allowed for the president's attendance of the opening match and the closing match of the tournament," said a Kremlin spokesperson.

"You know that the head of state surely has many responsibilities, which often keep him from attending certain events, but I can't give a precise answer to this question yet."

Russia, who beat Spain on penalties on Sunday to reach their first-ever World Cup quarter-finals since the break-up of the Soviet Union in 1991, will face Croatia at the Fisht Stadium in Sochi on Sunday morning (AEST).