European ministers have agreed to increase security on key international rail routes and improve intelligence sharing after the thwarted gun attack on a French train.
Home Secretary Theresa May and Transport Secretary Patrick McLoughlin were among representatives of nine countries at a summit in Paris called to formulate a co-ordinated response to the threat of an atrocity.
Mrs May said the attack on the Thalys service was "a shocking reminder of the threats we all face".
"Only by working together can we protect our citizens and defeat those who want to harm us," she added.
French interior minister Bernard Cazeneuve said after the talks that it was "essential to put in place co-ordinated operations on certain targeted routes".
The nations taking part include Germany, Belgium, the Netherlands, Luxembourg, Switzerland, Italy and Spain, who have agreed to "co-operate more closely still" over intelligence about the movements of suspected terrorists.
A man accused of a "targeted and premeditated" jihadist attack on a train to Paris has been charged by French prosecutors.
Moroccan national Ayoub El Khazzani was charged with attempted murder of a terrorist nature and was remanded in custody after a hearing in the capital.
Earlier, prosecutor Francois Molins said the 25-year-old was armed with a Kalashnikov assault rifle and 270 rounds of ammunition, as well as a Luger pistol, a bottle of petrol and a box-cutter when he boarded the train from Amsterdam.
He was spotted leaving a toilet cubicle, armed and topless, and was wrestled to the ground by two off-duty American servicemen and a 62-year-old British grandfather.
A French-American man was shot and wounded after reportedly stumbling across the attacker shortly beforehand.
The men have all since been awarded France's highest honour, the Legion d'Honneur, in recognition of their bravery.
Khazzani had initially claimed that he had only been intending to rob passengers as he was starving and living on the streets, and said he had found the weapons and mobile phone in a park where he was sleeping rough the night before.
Molins dismissed the story as "absurd" and "barely credible".
Two police officers were also wounded in the shootout at a Roma camp in France's Somme region, police said.Read the full story ›
The gunman foiled from carrying out a suspected terror attack on a high-speed train was armed with 270 rifle bullets and a bottle of petrol.Read the full story ›
Three Americans and a British grandfather who foiled a suspected terror attack on a high-speed train have received France's highest honour.Read the full story ›
A British grandfather who helped tackle a gunman wielding an AK-47 on a train in France will be awarded France's highest honour in recognition of his bravery.
IT expert Chris Norman, who now lives in France, will receive the Legion d'Honneur from French President Francois Hollande today, alongside three American men.
Between them, the four managed to subdue Moroccan jihadist Ayoub El-Khazzani, 26, after spotting him on the train travelling from Amsterdam to Paris on Friday.
Mr Norman, US Air Force serviceman Spencer Stone, National Guardsman Alek Skarlatos and Sacramento State University student Anthony Sadler, will reportedly be made chevaliers, or knights, of the Legion alongside an unnamed French citizen who first came across the gunman near a toilet on board.
An American serviceman has told press how he woke up from a deep sleep moments before tackling a gunman on a French train last week.
Speaking for the first time since the incident, Spencer Stone described turning around to see the suspected terrorist with what appeared to be an AK-47.
He said he and US National Guardsman Alek Skarlatos then tackled the man, after which Stone put him in a chokehold which eventually led to him passing out.
"He just kept pulling more weapons left and right," Stone said, adding that the gunman kept "jabbing" at him with a stanley knife.
Stone was speaking alongside Skarlatos, US student Anthony Sadly - a third American involved in the rescue - and US ambassador to France Jane Hartley.
The gunman who was disarmed by passengers on a train in France said he had only meant to rob people, a lawyer who interviewed him after the attack said on Sunday.
"He is dumbfounded by the terrorist motives attributed to his action," lawyer Sophie David who described him as her client, told BFMTV.
She said he was barefoot and wearing only a white hospital shirt and a boxer shorts for the interview at a police station in Arras, northern France, where the train stopped after the incident.
The man, named by French and Spanish sources close to the case as Ayoub el Khazzani, told David he found the Kalashnikov he was carrying in a park near the Gare du Midi rail station in Brussels where he was in the habit of sleeping.
"A few days later he decided to get on a train that some other homeless people told him would be full of wealthy people travelling from Amsterdam to Paris and he hoped to feed himself by armed robbery," David said.
French police were reportedly warned more than a year ago about the radical views of a gunman disarmed by US and British passengers on a train.
Spanish authorities told their French counterparts in March 2014 that Ayoub El-Khazzani had a "relationship with radical Islam", the Spanish El Pais newspaper reported.
It also claimed the 26-year-old Moroccan, believed to have visited Syria last year, had been included on a European anti-extremism police database as far back as 2012.
He was identified by counter-terrorism investigators as the gunman armed with an AK-47 assault rifle and a handgun who opened fire on the Amsterdam-Paris train on Friday.
French authorities also said El-Khazzani had lived in the southern Spanish city of Algeciras, frequenting a mosque which is under surveillance there.
He was transferred on Saturday morning to anti-terror police headquarters outside Paris and can be held for up to 96 hours
An American soldier who was hailed a 'hero' after taking down an armed gunman on a train travelling from Amsterdam to Paris has been released from hospital.
Spencer Stone was pictured with his left arm in a sling as he left the Clinique Lille Sud hospital in France this evening.
Stone was treated for knife wounds after tackling a 26-year-old man who opened fire on his train carriage armed with a Kalashnikov rifle.
Anthony Sadler, who also helped in the apprehension of the gunman, said his friend had shown great bravery in stopping the shooter.
He said: "He was the first one to jump on him, he's the one who got cut up ... none of us are injured but Spencer took a few injuries and he just had no fear."