Three people were injured when a gunman opened fire with an automatic weapon on a high-speed train traveling from Amsterdam to Paris on Friday.
French officials say two American passengers on board the train helped stop the gunman, who was also armed with a knife, by tackling him to the ground.
The suspect was arrested after the train stopped in Arras, 115 miles (185 kilometers) north of Paris, Interior Ministry spokesman Pierre-Henri Brandet said on French television BFM. Passengers were evacuated and police have secured the area.
"Thanks to the calm of two American passengers, we have avoided a tragedy," said French Interior Minister Bernard Cazeneuve.
Cazeneuve said the American passengers "were particularly courageous and showed great bravery in very difficult circumstances." One of the Americans was hospitalized with serious wounds along with another seriously injured person. A third person had minor injuries.
Some reports indicate the Americans were members of the U.S. military.
Twitter user @FreedomFilmLLC tweeted photos taken on the train, allegedly taken by his friend Christina Cathleen Coon, who said it was Marines who tackled the gunman.
Hey @thalys_en Whats going on? Reports of a gun and victim. pic.twitter.com/4ycpffIzzk— FreedomFilmLLC.com (@FreedomFilmLLC) August 21, 2015
Hey @thalys_en man had a machine gun with several rounds Luckily 3 U.S. Marines were right there & tackled him From friend of mine on train— FreedomFilmLLC.com (@FreedomFilmLLC) August 21, 2015
L'arrestation du suspect a Arras #Thalys #Arras #OnVoitPasGrandChoseMaisQuandMeme #Arrestation #Fusillade #Train pic.twitter.com/Ywgt1pk6lZ— David C. (@DavidGekko) August 21, 2015
Additional reporting from Associated Press.