American servicemen overpowered a gunman armed with a Kalashnikov who opened fire on a high-speed train travelling from Amsterdam to Paris, preventing what the White House said could have been “far worse tragedy.” According to initial information from investigators, at least two of the men who tackled the gunman were American troops who had apparently heard him loading his weapons in a toilet cubicle and confronted him after he came out. Two people were wounded in the incident, with the Pentagon confirming that one was a member of the US military. The gunman had a Kalashnikov, an automatic pistol and a box cutter, one police source told AFP. The suspect, who was arrested when the train stopped at the northern French town of Arras, was a 26-year-old from Morocco who was known to the intelligence services, French investigators said. US President Barack Obama praised the passengers for their actions. “The president expressed his profound gratitude for the courage and quick thinking of several passengers, including US service members, who selflessly subdued the attacker,” a White House official said. “Their heroic actions may have prevented a far worse tragedy.” The motives for the shooting were not immediately known, although French prosecutors said counter terrorism investigators had taken over the probe.