Ukraine's intelligence agency said it has thwarted a plot to attack the Euro 2016 football tournament in France.
The SBU said it had been following a French man since December. They allowed him to purchase five machine guns, two rocket-propelled grenades and other weapons before he was arrested on the Ukrainian-Polish border last month.
The SBU didn't identify the man, but said he was driven by ultra-nationalist views and planned 15 attacks on bridges, railways and other pieces of infrastructure for Euro 2016.
Extremist attacks are a major concern for French authorities as they prepare to host the month-long tournament. It's being held at stadiums in the Paris area and eight other cities from Friday through to July 10.
Islamic State extremists have threatened France during the tournament. However, authorities haven't confirmed specific dangers.
France is deploying 90,000 security forces for the tournament, and French president Francois Hollande said on Sunday night that the threat of attacks will not stop it from being successful.
Ukrainian authorities released photos of a fair-haired man, with his face blurred, holding various weapons.
The SBU said the French man came up on their radar last year during his stay in eastern Ukraine, and where he was "trying to establish ties with Ukrainian troops under the guise of volunteering".
Ukrainian troops and Russia-backed separatists have fought in the east since April 2014, killing more than 9,400 people. It was not immediately clear which side of the conflict the French man had stayed at.
"The Frenchman spoke negatively about his government's migration policies, the spread of Islam and globalisation," the SBU said. "He also said that he wanted to perpetrate acts of terror in protest."