Martin Kallen, tournament director for Euro 2016, which will be staged across France from June 10-July 10, told Germany's Sport Bild magazine that organisers and French security services had been working together to discuss options in case of a perceived threat.
Security concerns have mounted in the wake of the Nov. 13 Paris attacks when Islamist militants killed 130 people in bars, restaurants and a concert hall in and around the capital.
Three suicide bombers also blew themselves up outside the Stade de France -- venue for the Euro 2016 opening match, final and five other matches -- where France were playing Germany in a friendly international football match.
Kallen said Euro 2016 games could be moved at short notice bringing in the scenario of playing without any fans present "because the spectators who have tickets for the match in question wouldn't have enough time to organise travel and a hotel room.
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"Safety and staging the tournament takes priority over everything else," he told the weekly sports magazine.
At a news conference in Paris later on Wednesday Jacques Lambert, head of the Euro 2016 local organising committee, sought to play down the likelihood of teams playing in empty stadiums.
"As of today that's not what we foresee," he told reporters as officials outlined the additional security measures fans can expect.
Some 2.5 million spectators are expected at 10 stadiums for 51 matches involving 24 teams.
The Stade de France will be watched over by some 1200 security officials.
The average stadium security presence will be 900 strong, plus 200 volunteer ushers, 80 medics - about 30 percent more staffing than at normal matches. CRS riot police and Gendarmerie divisions will also be deployed in the host towns.
(Reporting by Simon Carraud; Writing by Mitch Phillips, editing by Ken Ferris and Dominic Evans)
