One of the seven terrorists who took part in the co-ordinated and brutal massacre of almost 130 people in Paris on 13 November may have entered the EU through a Greek island, it has emerged last night, as France’s President described the group’s actions as an “act of war”.

The man, who was carrying a Syrian passport when he died, apparently passed through the island of Leros last month before taking part in the series of bloody attacks across the French capital which left at least 129 people dead and about 99 critically injured in hospital. A Greek police source said the passport’s owner had arrived on a small vessel from Turkey with a group of 69 refugees and had his fingerprints taken by Greek officials.

Police said one terrorist had an Egyptian passport while another had been identified by his fingerprints as a French national who was already known to security services. Three of the attackers are believed to have come from the Molenbeek district of Brussels, where heavily armed police teams backed by bomb disposal units made five arrests after raids on three addresses.

Belgian justice minister Koen Geens has confirmed that the arrests were linked to the Paris attacks. He said that they came after Paris police found a grey VW Polo rental car with Belgian number plates near the scene of the Bataclan concert hall, where the most brutal shooting took place. “There were arrests relating to the search of the vehicle and person who rented it,” Mr Geens said.

He said Belgian anti-terror services flagged up a possible terrorist connection as soon as the name of the car hirer was passed to them, because the hirer’s brother was on their watch list. The man who rented the car was “as far as we know, still alive”, he said. Paris police searching for another car with Belgian plates, a black Seat, later found it near the Père-Lachaise cemetery.

François Molin, Paris prosecutor, said there were three teams of terrorists working together to co-ordinate attacks and said six terrorists had blown themselves up and a seventh was shot dead by police. One of the terrorists was identified by fingerprints as a man born in 1985 in Courcouronnes suburb south of Paris, who had previously been arrested but had not been to prison, officials said.

On 14 November, Islamic State claimed it had carried out the atrocities, which targeted mostly young people enjoying a night out in bars and restaurants, and at a rock concert and a football match. The group issued a statement saying the venues had been “carefully chosen” and warning that the attack by “brothers carrying explosive belts and guns” was “only the start of the storm”.

Molenbeek, on the east side of Brussels, is home to a large community of immigrants from Morocco and Turkey. It is also one of the poorest places in the country. In January, two suspected terrorists were killed there after a shoot-out with Belgian police, shortly after the Charlie Hebdo shootings.

As Parisians struggled to come to terms with the scale of the tragedy that had engulfed their city – the second serious terrorist attack this year – the French President, François Hollande, made a defiant speech in which he described the events as “an act of war that was prepared, organised and planned from abroad, with complicity from the inside”.

Local authorities were given permission to impose curfews if necessary. Many municipal buildings were closed on 14 November, with sports events cancelled and large gatherings banned for the next five days. To help the many injured, residents are also being urged to donate blood.

The UK has stepped up its security in the wake of the attacks, which Downing Street said may have claimed the lives of a “small number” of British victims. The first confirmed British casualty was Nick Alexander, who is understood to have been working in the merchandise stall at the Bataclan concert hall, where at least 89 people were gunned down by terrorists wielding Kalashnikov rifles. Another confirmed casualty was Valentin Ribet, a Paris-based lawyer who trained at the London School of Economics.

Survivors of the Bataclan massacre told how three or four gunmen wearing black burst into the concert hall and opened fire. “The blood was everywhere, but what struck me was the calm of the gunmen. They were prepared. They knew exactly what they were doing, and they had one goal, just to kill the most people they could,” said Julien Pearce, a journalist who was present.

A graphic video taken by a French journalist showed how people burst out of the venue’s emergency exits as they tried to escape the gunfire, with some hanging out of upstairs windows in an effort not to be spotted. Others played dead by lying among the corpses.

On the streets outside the Bataclan, the signs of the massacre which took place inside were still evident when Parisians arrived to pay their respects early on 14 November. Pools of dried blood and discarded surgical gloves could be seen by the roadside near the music venue.

Although police had cordoned off the area immediately outside the Bataclan, the word “eagles” was still visible, spelt out in thick black letters above the door through which more than 1,000 excited music fans had filed on their way to see the American band Eagles of Death Metal only a few hours previously.

The bombers were reported to have been thwarted from entering the Stade de France, preventing mass casualties among the tens of thousands inside.

The Wall Street Journal quoted a guard as saying one of the attackers presented a ticket but was found to be wearing an explosives when frisked about 15 minutes into a France-Germany friendly. While attempting to back away from security, the attacker detonated the vest.

Three minutes after the blast, a second person blew himself up and a third bomb was detonated at a nearby McDonald’s restaurant, police said, killing another attacker.

Throughout the morning, Parisians arrived in disbelief to leave flowers, write tributes or simply talk to one another. A tearful Yann Sciardis, 27, who lives only 300 yards from the venue, described how he had been forced to stay the night at his girlfriend’s parents’ house when news of the attacks began filtering through on his phone as he drank in a bar with friends.

“I thought: ‘Oh no, not again,’” he said. “I’m devastated. I’m shocked. I don’t know what to think about it. What happened affected every Parisian – the bars, the concerts. This is what you do on a Friday night. It’s part of me.”

His voice breaking, he continued: “I don’t want to be scared. We don’t need to be scared. We have to show them that we want to live. I had to be here, and now I understand why. I’ve spoken to some people and it feels good to speak about it. This is where I live. I want to be here.”

Ari Seitsonen, 47, who also lives close to the Bataclan, was working late when news of the massacre broke and stayed up all night in his office, too afraid to leave. “Of course it reminds us of January,” he said in reference to the terrorist attack on the offices of Charlie Hebdo earlier this year. “Paris is a target. It’s a symbol for liberty.”

Yet only a few streets away from the site of the massacre, Parisian life appeared to be continuing as normal. People sat outside cafés drinking coffee and chatting; a large queue formed outside an artisan boulangerie; a woman in sunglasses strolled by, walking her dog on a pink lead.

“I’m happy to see that Paris lives on,” Mr Seitsonen said. “People are going through their routines.

“Life must go on. But time will show how Paris will change, and I’m sure it will.”