A suspect was arrested Friday after he opened fire aboard a train from Amsterdam to Paris, French and international news outlets reported. A Briton and an American were reported to have been "seriously" wounded in the attack, the Telegraph reported.

A third individual, French actor and filmmaker Jean-Hugues Anglade, was injured as well, and was said to have signaled an alarm over the incident. Bernard Cazeneuve, the French interior minister, was on his way to the scene.

French President François Hollande expressed concern for the victims via Twitter and vowed to launch an investigation.

Police said they were not ruling out terrorism as a possible motive. The suspect reportedly has not said anything since his arrest. For now, the case is being treated as a criminal investigation.

The man was reportedly taken down by U.S. Marines aboard the train, the Telegraph reported. The service members heard what sounded like a gun being loaded inside a restroom and tried to restrain the suspect. The man then opened fire, wounding the three individuals, authorities said.

France has remained on high alert since Islamic extremists stormed the Paris offices of satirical French magazine Charlie Hebdo and a Jewish delicatessen in January. Twelve people were killed during the attack on the magazine office, and four hostages were killed at the kosher deli.

Separately, a man beheaded his boss and planned to blow up a gas plant in France in an attack prosecutors have sought to prove was inspired by the Islamic State group, which is also known as ISIS or ISIL.

Following Friday's attack on the train, a Twitter user tweeted a photo that appeared to show police restraining an individual on a train platform. The contents of the image has not yet been verified.