Euro 2016 matches could be moved to different venues and played behind closed doors in the event of terror attacks or threats.
Organisers of the tournament to be played in France this summer are confident that security measures for the event will ensure it runs safely.
But contingency plans have been put in place following the co-ordinated terror attacks on Paris on November 13 last year, which included an assault on the Stade de France during a friendly between France and Germany.
Suicide bombers targeted the area outside the stadium and the players heard the explosions, but the match continued.
The Stade de France will host the opening game and the final of Euro 2016, as well as other matches.
A UEFA spokesman told Press Association Sport: "We are working on contingency plans even though we are not aware of any specific threat.
"And we work on multiple scenarios, including the possibility to have matches postponed, moved to other venues or played without spectators. These are only some of the scenarios we are working on because we take the security of all participants (players, fans, etc) very seriously, but we are confident that all security measures will be in place for a safe and festive Euro."
Wednesday marks 100 days to go to the start of the finals, with Euro 2016 president Jacques Lambert set to face the media in Paris to discuss the latest arrangements in relation to the tournament.
Hosts France face Romania in the opening game of the tournament on 10 June.