A heroic US airman told tonight for the first time how he and his childhood friends brought down a gunman intent on massacring the passengers of the Amsterdam to Paris express train.

Spencer Stone revealed how he woke from a deep sleep to see a man holding an assault rifle and that it 'looked like it was jammed and it wasn't working'.

Speaking for the first time about his crucial role in thwarting the terrorist attack in northern France in Friday he said the trio decided they had to 'do something or die'.

US serviceman Spencer Stone answering reporters' questions at the US embassy in Paris on Sunday

Pat on the back for a hero: US ambassador to France Jane Hartley with (l-r) Spencer Stone, Anthony Sadler and Alek Skarlatos at the press conference - two days after a 25-year-old Moroccan opened fire on the train

Jane Hartley, Spencer Stone and Anthony Sadler look on as Alek Skarlatos recalls how they foiled the gunman

Mr Stone said: ‘I just wanted to survive and for my friends and everyone else on the train to survive.

‘He was ready to fight to the end, so were we.

‘I tackled him and Alek came down and put him in a choke hold and kept hitting him.

‘He had a box cutter and he started to go at me with that.

‘He let go and we started punching him all three of us and Alek hit him in the head with a pistol.

It was either do something or die Anthony Sadler, American hero

‘We kept hitting him until he was unconscious.’

Stone spoke at a live news conference at the U.S. ambassador's residence in Paris along with Anthony Sadler and National Guardsman Alek Skarlatos.

The trio of Americans who foiled an attempted terrorist attack on a train bound for Paris said on Sunday they had no choice but to fight for their lives.

'At that time he was cocking the AK-47,' said Anthony Sadler, a California college student, from the U.S. ambassador's residence in Paris. 'So it was either do something or die...In times of crisis...do something. Hiding or sitting back is not going to accomplish anything.'

'I'm still waiting to wake up,' he said. 'It's like a movie scene or something.'

'I was thinking about survival,' said Spencer Stone, who serves in the Air Force. 'It was to survive and for everybody else on the train to make it.'

Spencer, who is visibly injured from the terror attack, said he was stabbed in the neck and hand

Stone is hailed not only for being the first to grapple with the attacker, but for helping to stop the bleeding in a French-American passenger wounded by a bullet.

Stone, wearing a sling on his left arm, was wounded in the attack and said he will receive further medical treatment in Germany.

In the beginning it was mostly gut instinct, survival Alek Skarlatos

Stone said the attacker kept pulling out weapons from his bag, and that he was stabbed in the neck and sliced on his hand.

Stone said his thumb was reattached during his hospital stay in Lille. He thanked the French doctors, police officers and others.

Skarlatos said military training played a part in subduing the gunman.

'In the beginning it was mostly gut instinct, survival,' he said. 'Our training kicked in after the struggle.'

Mr Skarlatos said: ‘His intentions were pretty clear. He had a lot of ammo.’

Mr Sadler added: ‘He came into the car and started cocking the AK 47 so I guess he was intent.

Healing: Spencer Stone emerged from the central hospital in Lille, France, wearing bandages and a sling a day after tackling a terrorist down

‘The gunman would have been successful if Spencer had not had got up.

‘I don’t know what I would have done if I was by myself.

‘But I saw Spencer get up and I saw Alek get up and they are my close friends.

‘These are my friends and I was the third person to get up

‘I thought like I got to do something.’

I just wanted to survive and for my friends and everyone else on the train to survive Spencer Stone

In the glare of the hastily assembled press conference Ambassador Jane Hartley described the young men as ‘true heroes’ and said she was ‘so proud to be sitting here with you.’

Mrs Hartley said: ‘You often hear the word hero but in this case I think that word has been more appropriate.

‘I know these young men sitting with me won’t like it as during the brief period we have known each other they are so humble, but they are truly heroes.

‘When most of us would run away Spencer, Alek and Anthony ran into the line of fire, saying ‘let’s go’. And those words changed the day for many.

‘They demonstrated the very best of America with their selfless actions in tackling the assailant.

‘As President Obama said, in his phone call with President Hollande, these three brave young Americans, along with the French and British passengers, demonstrated remarkable bravery and acted, without regard for their own safety, in order to subdue a heavily armed individual who appeared intent on causing mass casualties.

He wore a cast at the press conference and said thumb was reattached during his hospital stay in Lille, France. U.S. Ambassador Jane Hartley (also pictured) praised the three Americans as heroes

‘As a representative of my country, as an American and as a mother of a son not much older than you I’m so proud to be sitting here with you. Thank you so much.’

The heroes dismissed claims by El Khazzani’s lawyers that he was not a terrorist and was only planning to rob the passengers.

They are truly heroes. When most of us would run away, Spencer, Alek and Anthony ran into the line of fire, saying `Let's go' U.S. ambassador to France Jane Hartley

'We often use the word hero and in this case I know that word has never been more appropriate,' Hartley said.

'They are truly heroes. When most of us would run away, Spencer, Alek and Anthony ran into the line of fire, saying `Let's go.' Those words changed the fate of many.'

The young men are currently the ambassador's honored guests just a stone’s throw away from Paris’ prestigious Champs Elysee.

A source at the US Embassy told MailOnline: ‘They are the ambassador guests. They had drinks and pizza last night.

‘The young men joked they had checked it [the US ambassador’s residence] on [travel guide website] Expedia and decided it was ok.

‘They were brought down to Paris in the ambassador’s car.

‘She is very proud of them, we all are.’