An airman was wounded by a gunman on a train from Amsterdam to Paris on Friday, according to an internal Pentagon report obtained by Military Times.

The report did not say how the airman was wounded, but media outlets have reported that U.S. troops overpowered the gunman, preventing him from killing the train's passengers.

Three other service members were involved in the incident: two Marines and one service member whose branch was unknown at press time, the report says.

Defense officials in the U.S. and Europe declined to say what branches of service the troops were from.

"At this point, we can only confirm that one U.S. military member was injured in the incident; the injury is non life-threatening," said Air Force Lt. Col. David Westover, a spokesman for U.S. European Command. "We will continue to monitor the situation and provide updates as they become available."

The State Department referred questions about the incident to the Defense Department, which deferred to EUCOM.

A local French newspaper initially reported that two Marines aboard the train helped apprehend the gunman, a 26-year-old Moroccan man armed with an automatic rifle and knife. Media reports give varying figures for how many people were injured in the incident.

French Interior Minister Bernard Cazeneuve called the Americans "particularly courageous" and said they "showed great bravery in very difficult circumstances," the Associated Press reported.

Staff writer David Larter contributed to this report.