An American serviceman who was one of four men to subdue a gunman armed with an AK-47 on a train from Amsterdam to Paris, has been stabbed in the US.

US Airman Spencer Stone is in a stable condition in hospital following the incident in Califronia on Wednesday evening.

Together with US National Guardsman Alek Skarlatos, Anthony Sadler, and British businessman, Chris Norman, they had fought suspected 26-year-old Moroccan jihadist Ayoub El-Khazzani on August 21, stopping him from rampaging through the carriages.

They were presented with the Legion of Honour medal in France.

A spokesman for the US Air Force confirmed the incident, saying: "He (Mr Stone) was involved in an incident and is in a stable condition."

He added: "At approximately 1 a.m. PST (Pacific Standard Time), Airman 1st Class Spencer Stone, Air Force service member who helped thwart a gunman's attack on a French train in August, was involved in a stabbing incident in Sacramento.

"He was transported to a local hospital."

Three days after the train attack, all four men who stopped the gunman were presented with France's top honour for bravery by French president Francois Hollande.

Mr Stone, who was stabbed as he held back the attacker, said he just wanted to survive, and for his friends and for everyone else on the train to make it.

He praised French medical staff and said an unknown French man, who first came across the gunman near a toilet on the 554-passenger train, "started the struggle at first, I think he deserves a lot of credit".

Mr Stone said: "I turned around and he (the gunman) appeared to have what looked like a AK-47.

"It looked like it was jammed or wasn't working and he was trying to discharge the weapon. Alek hit me on the shoulder and said, 'let's go'.

"We ran down, tackled him and hit the ground. Alek tackled him and grabbed the gun out of his hand while I put him in a chokehold. It seemed like he kept on pulling more weapons - left and right.

"He pulled out a handgun. Alek took that. He took out a box cutter and was jabbing at me with that. We let go and all three of us started punching him while he was in the middle of us."