Spencer Stone, one of three Americans who helped foil a terror attack on a French train in August, was stabbed in Sacramento on Wednesday night, the U.S. Air Force confirmed to NBC News.

Airman First Class Stone was in stable condition on Thursday, an Air Force spokesperson said. Police said he was stabbed more than once and was being treated for "non life-threatening but very significant injuries."

Stone was out with four friends, a male and three females, when he became involved in an argument with at least two men around 12:45 a.m. PT near some popular bars in downtown Sacramento, police said.

It appeared that a "verbal argument" ended up on the street and led to a physical confrontation, a Sacramento Police Department spokeswoman told NBC News.

Deputy Chief Ken Bernard of Sacramento Police called the incident as "an altercation between two groups of folks who were enjoying the nightlife. This was not related to terrorism in any way and we know it was not related to what happened in France."

Bernard said the two suspects, described as Asian males in white T-shirts and blue jeans, fled the scene in a late-model Toyota Camry.

Stone, 25, tackled Morocco-born Ayooub El-Khazaani after the heavily armed terror suspect opened fire on a Paris-bound train in August.

Stone was stabbed with a box cutter during the bloody struggle with El-Khazaani, and needed surgery to reattach part of his hand. He received France's highest award, the Legion d'Honneur, along with childhood friends Alek Skarlatos and Anthony Sadler, for his selfless actions.

Skarlatos tweeted Thursday morning: "Everybody send prayers out to the stone family today."

Stone said after the attack he acted in the interest of "survival," not only for himself but for everyone else on the train. "He seemed like he was willing to fight to the end, so were we," Stone said of El-Khazzani. (Source: NBC News)

Story Date: October 9, 2015