French President Francois Hollande says that the threat of extremism won't stop the European Championship soccer tournament from being successful.

Hollande said in an interview on Sunday with France Inter radio that precautionary measures throughout the matches, including a 90,000-strong security force, will ensure the matches scattered in 10 French cities are safe.

Hollande said France decided to go ahead with Euro 2016 despite two waves of attacks last year, and make it a "festival for people and for sports."

But he said that spectators at the monthlong tournament, which starts on Friday, must accept security checks as they enter stadiums and fan zones.

Hollande added that "this threat, alas, will exist for a long time so we must guarantee this great event ... is successful. It will be."