AKIPRESS.COM - U.S. Air Force airman Spencer Stone, one of the three Americans who thwarted an August train attack in France, was stabbed several times during a fight outside a Sacramento bar early on Thursday and was hospitalised in serious condition, police said.

The fight was not related to Stone's role in subduing the gunman on a train headed to Paris and there was no connection to terrorism, Sacramento Deputy Police Chief Ken Bernard told a news conference. Stone's assailant, who has not been caught, is not believed to have known Stone's identity, Bernard said.

Bernard would not say what caused the fight that led to “significant injuries” to Stone, who was taken to UC Davis Medical Centre in Sacramento.

Stone and two friends, Anthony Sadler and Alek Skarlatos, who is part of the Oregon Army National Guard, took down a man armed with a box-cutter, a pistol and an AK-47 assault rifle on a high-speed train bound for Paris in August. They won accolades for their actions from the presidents of France and the United States.

The three men, who grew up in the Sacramento area, were touring Europe, partly to celebrate Skarlatos' return from a tour of duty in Afghanistan, at the time of the train incident. They were feted back home in Sacramento with a parade.

After the fight on Thursday morning, police initially did not believe Stone would survive, but doctors were able to control his bleeding, the Sacramento Bee reported. The medical centre said late on Thursday that Stone was in serious but stable condition in its intensive care unit, reports Reuters.