Jean-Claude Juncker, President of the European Commission, has rejected calls to rethink the European Union’s open doors policy on migration. Dismissing suggestions that open borders led to the attacks, Mr Juncker said he believed “exactly the opposite” – that the attacks should be met with a stronger display of liberal values including open borders.

Speaking at the G20 summit in Antalya, Turkey, Mr Juncker said that the perpetrators of Friday’s terrorist attack in Paris, which claimed more than 125 lives, should not be confused with genuine asylum seekers or refugees.

Addressing an audience of journalists in both French and English, Mr Juncker said: “I read here and there, I hear here and there that the true explanation of the events that took place in Paris is due to the fact that Europe is a continent with open borders, a continent that showed a certain generosity when it comes to dealing with the refugee crisis: this is not my analysis.

“My belief is exactly the opposite of those and those who believe that the explanation underlying the attacks would be the European model. He must see that those who organized these attacks and those who perpetrated them are exactly those refugees flee and not the reverse. And therefore there is no need to review the whole European refugee policy.”

In response to questions from the floor, he continued: “I try to make it crystal clear that we should not mix the different categories of people coming to Europe. The one who is responsible for the attacks in Paris cannot be put on an equal footing with real refugees, with asylum seekers and with displaced people.

“These are criminals and not refugees or asylum seekers. I would like to invite those in Europe who are trying to change the migration agenda we have adopted – I would like to invite them to be serious about this and not to give in to these basic reactions. I don’t like it.”

The Greek authorities have confirmed that two, possibly more of the eight jihadists who carried out Friday’s attack gained entry to Europe via the Greek island of Leros, where earlier this year they claimed to be asylum seekers fleeing the war in Syria.

When quizzed on this detail, Mr Juncker replied: “I do not believe that the person in question to be categorized as a refugee or asylum seeker. I believe that in his case it is a migrant who has abused the procedures.

“Do not confuse the perpetrators of criminal acts in Paris with the asylum seekers, with migrants who have good reason to knock on our doors; and do not confuse those who committed these atrocities with those who flee the philosophy and mentality that inspire acts that unfortunately we have seen in Paris.”

He denied that the breach of Europe’s borders by these two terrorists demonstrated that the Schengen open border agreement was fatally flawed, saying: “The decision of the French President for a while reintroducing border controls is expressly provided for in the Schengen Agreement, in order to respond to the location of such events.”

This morning, Britain’s Home Secretary Theresa May confirmed that Britain’s terror alert level is set to “severe”, meaning that a terrorist act is “highly likely”.

About 450 radicalised Britons have already returned from Syria and may be poised to strike. Islamic State has also been urging its followers in Europe who are unable to make it to Syria to stay at home and carry out attacks on Europe’s streets.

Speaking to the BBC’s Andrew Marr, Mrs May said: “We’ve been at that threat level for over a year now and of course we operate at that threat level and since the attacks [in Paris] that took place on Friday and there’s been an increase in peace presence on the streets and at some events.

“Our border force have increased checks they’re making at the border, more screenings of freight vehicles and other vehicles as well. People going through our ports will see a greater police presence.”