Portugal coach Fernando Santos says his team could be a target for terrorists at Euro 2016 due to the presence of Cristiano Ronaldo.
Security will be high at this summer's tournament, with France still in an official state of emergency following the terror attacks in Paris in November that left 130 people dead, with three suicide bombers striking near the Stade de France.
Paris chief of police Michel Cadot reportedly wants to reduce fan zone plans for the tournament, while the U.S. State Department has warned there could be attacks at venues near stadiums and issued a travel alert to its citizens covering the entire continent of Europe this summer.
Europol director Rob Wainwright, though, has said it will be difficult for terrorists to carry out an attack given the level of security in France this summer.
Speaking after his side's 1-0 friendly loss to England on Thursday, the Portugal coach said: "As everybody knows, Portugal is considered one of the high-risk teams due to the presence of Cristiano Ronaldo, but we are prepared for this.
"In reality, this will be the responsibility of the French security. Our fans will have to understand that at certain moments we won't be able to release our players as we would like."
Portugal's campaign gets underway against Iceland in St Etienne on June 14 and they then play Austria at Paris' Parc des Princes on June 18, and face Hungary at the Stade de Lyon on June 22.
Real Madrid forward Ronaldo missed the England game at Wembley as he has been given time off to rest following Saturday's Champions League final victory over Atletico Madrid and has been relaxing with friends with Ibiza.
The 31-year-old scored 51 goals in 50 games all competitions for Madrid last season but has been suffering with injuries in recent weeks and was not at his best in the Champions League final despite completing the game.
Ex-Madrid and Spain defender Jose Emilio Amavisca says the situation appears similar to that before the 2014 World Cup, when Ronaldo ended the club season with a serious knee problem and made little impact in Brazil as Portugal exited at the group stage.
"I believe [Ronaldo] is arriving worn out and not 100 percent," Amavisca said in AS. "He will not shine at the Euros, the same as happened at the World Cup.
"He wants to play all the games and all the minutes and there is no body that can take all that. We have seen how he ended the Champions League final and I believe the same thing will happen as at the last World Cup."
Meanwhile, Ronaldo has repeated his desire to stay at Real Madrid for the rest of his career and continue playing into his 40s.