France must be prepared for further domestic terror threats, French President Francois Hollande said Tuesday, just days after several bystanders foiled a possible terrorist attack aboard a Thalys high-speed train traveling from Amsterdam to Paris. Hollande urged heightened security and alertness, telling journalists and diplomats in Paris that the attack on the train would not be the last terror incident in France.

"We are always exposed and Friday's aggression on the Thalys Amsterdam-Paris train could have resulted in monstrous carnage without the courage of several passengers," Hollande said referring to the heavily armed suspect, as reported by Agence France-Presse. "This attack is fresh proof that we must prepare for other attacks and therefore protect ourselves," he said.

Ayoub El Khazzani, 25, boarded an Amsterdam-bound passenger train Friday armed with a Kalashnikov assault rifle, a Luger automatic pistol, ammunition and a box-cutter. Three off-duty U.S. servicemen and a few bystanders wrestled Khazzani to the ground, sustaining injuries while averting what many authorities believe was a terrorist attempt. 

GettyImages-485078562 French President, Francois Hollande (left) received France's U.S. Ambassador Jane Hartley (center) and honorees at Elysee Palace Monday in Paris. Spencer Stone (second from right), Anthony Sadler (right) and Alek Skarlatos (second from left) were awarded the Legion d'Honneur after helping to overpower a gunman on board a high-speed train after he opened fire. France must be prepared for future terror attacks, Hollande said Tuesday. Photo: Getty Images

Khazzani is being detained by police and can be held until Tuesday night, at which time under French law he needs to be charged with a crime or released. The Moroccan suspect who has lived in several European countries has said that he wanted to rob the train, not commit a terrorist act.

The Thalys attack came just several months after two armed gunmen, Said and Cherif Kouachi, stormed the offices of the satirical weekly Charlie Hebdo, killing 12 and wounding many more. The January assault in Paris was the worst domestic attack France had seen in decades, and it rocked both France and the rest of Europe.

"[T]he world is not only threatened by global warming, it is facing a terrorism that has never before reached this level of barbarity, nor seriousness in decades," said Hollande.