Three people have been wounded, including one American, in a shooting on a high-speed train running between Amsterdam and Paris. The shooting occurred on Friday, according to Yahoo! News.

A man has been arrested and is being held in custody. Early reports say that two U.S. Marines were on the train with the shooter. They overpowered the man so that he could be apprehended. The gunman's motives are unknown at this point.

"Talking about a terrorist motive would be premature at the moment," Pierre Henry Brandet, military spokesperson, said. France is currently still on high security alert following an attack from Islamist militants in January that killed 17 people.

"It's important for me, together with the president of the Republic and the prime minister, to express to the two American passengers, who have been particularly brave, who acted during a very difficult situation, all our gratitude for what they did. Without them we could have faced a terrible tragedy," French Interior Minister Bernard Cazeneuve said, according to NBC News.

The suspect was armed with a knife and an automatic rifle. The investigation into this shooting event is ongoing.

Shots were fired, and one report says there is a woman who is "seriously" injured, according to The Mirror. Both the Marines involved were wounded, one by a gunshot and the other by the knife.

"Everything is being implemented to shed light on this tragedy," French President Francois Holland said, The Mirror reported.