LIVE: Paris Terror Attacks - French say there were three 'assault teams' involved in attacks
* Militant group said 'Paris would remain a top target'
* French President Hollande: "France will be ruthless in its response to Islamic State."
* State of emergency: borders closed and Paris curfew
* Concert hall, football stadium and restaurant attacked
* Three terrorists killed as 125 hostages freed
* Total death toll: 100 killed in Bataclan, another 28 killed in other locations
* Dozens more are seroiusly injured
Paris was hit by "three teams of attackers", a prosecutor said.
The attackers who killed 129 people in Friday night's wave of shootings and suicide bombings in Paris appeared to be made up of three teams, Paris Prosecutor Francois Molins said on Saturday.
"We can say at this stage of the investigation there was probably three coordinated teams of terrorists behind this barbaric act," he told a news conference.
He also confirmed that French authorities had a security file for Islamist radicalisation on one of the attackers, who also had a criminal record, but had never spent time in jail.
He added that a person who had hired one of the cars used in the attacks was stopped at the Belgian border.
The official death toll is now at 129 people - with another 352 people injured. It's understood 99 of these people are in a critical condition.
Earlier this evening, it was announced that the Syrian passport found near the body of one of the gunmen who died in Friday night's attacks belonged to a refugee who passed though Greece in October, a Greek minister said.
"The holder of the passport passed is believed to have passed through the island of Leros on 3 October 2015, where he was identified according to EU rules,” said Nikos Toscas, Greece’s deputy minister in charge of policing.
A Greek police source told Reuters that European countries had been asked to check the passport holder to see if they had been registered.
While this heavily implies that one of the gunman came into Europe along with refugees, Syrian passports are known to be valuable currency amongst those trying to enter Europe, and it is not yet confirmed whether the holder of the passport is indeed the perpetrator.
Earlier today it was confirmed that at least one of the bombers in the Paris attacks was young Frenchman who was already known for links to Islamic extremism.
It is unclear whether he is same person identified as a possible attacker at the Bataclan concert hall, where at least 80 people were killed.
Islamic State have claimed responsibility for the deadly attacks in Paris that killed 127 people, warning that France would remain a “top target” unless it stops its air strikes in ISIS held territories.
The militant group says the Paris attacks were a response to "insults of Islam's prophet and airstrikes in Islamic state territory". The group's foreign media arm, Al-Hayat Media Centre, said in a video that as "long as you keep bombing you will not live in peace. You will even fear traveling to the market."
The militants, who appeared to be French citizens, can be seen sitting cross-legged in a group wearing fatigues and holding weapons in what appears to be a wooded area.
The video showed the militants burning their passports and saying: "Indeed you have been ordered to fight the infidel wherever you find him - what are you waiting for? There are weapons and cars available and targets ready to be hit.
"Even poison is available, so poison the water and food of at least one of the enemies of Allah.
"Terrorise them and do not allow them to sleep due to fear and horror," it ends.
In a statement published online, the jihadist group continues: "This attack is just the start of a storm and a warning for those who wish to draw lessons.
"Eight brothers carrying explosive belts and guns targeted areas in the heart of the French capital that were specifically chosen in advance: the Stade de France during a match against Germany which that imbecile Francois Hollande was attending; the Bataclan where hundreds of idolaters were together in a party of perversity as well as other targets in the 10th, 11th and 18th arrondissement
"France and those who follow its path must know that they remain the principle targets of the Islamic State."
Earlier on Saturday, French President Francois Hollande accused ISIS of orchestrating the "cowardly" attacks, and said the group had carried "out an act of war".
President Hollande said France would remained "unbreakable", vowing that the nation would be "merciless" in hunting down those responsibility for the Paris attacks.
"We will work alongside our allies to fight this terrorist menace ... France is strong and even if she is wounded she will get up always and nothing will hold her down, even if we are feeling the grief now ... We will defend ourselves."
Authorities in France believe that all eight of the attackers responsible for the country's worst night of violence since the Second World War are now dead, including seven who blew themselves up with suicide bombs.
But the city's prosecutor said it is possible there are still other terrorists on the run.
A state of emergency was declared in France after the attacks, which Mr Hollande described as an "abomination".
Police leave was cancelled and some 1,500 extra soldiers have been mobilised to guard official buildings and religious sites, while controls have been re-imposed at the country's borders.
The country's schools and universities, which often open on Saturdays, have been ordered to remain closed.
Mr Hollande, who has cancelled a planned trip to Turkey for the G20 summit this weekend, called an emergency meeting of senior government and security figures at the Elysee Palace.
In a night of carnage in the French capital:
:: Police stormed the Bataclan concert hall where hostages were being held but attackers, wearing suicide belts, blew themselves up, leaving 80 people feared dead. A witness said that one of the gunmen shouted Islamist slogans and said "This is for Syria" - a possible reference to France's participation in airstrikes against Islamic State.
:: Two suicide attacks and a bombing took place at the Stade de France stadium, where Mr Hollande was among thousands of football fans watching the national side play a friendly fixture against Germany.
:: Gunmen targeted bars and restaurants in the 10th and 11th arrondissements of central Paris. As many as 18 people died when the terrace of the La Belle Equipe was sprayed with gunfire, while around 14 people were killed at Le Carillon bar-cafe, and there was shooting at the nearby Cambodian restaurant Le Petit Cambodge.
During a visit to the Bataclan concert hall in the early hours Mr Hollande said the country will be "merciless" against those who have attacked them.
"We will lead the fight. We will be merciless," said the president.
Messages of sympathy and support were issued by world leaders, while ordinary people around the globe turned to social media to express their shock.
US president Barack Obama said the violence in the French capital was "was an attack on all of humanity", while the Vatican condemned it "in the most radical way".
The foreign ministry of Iran - whose president Hassan Rouhani cancelled a trip to France - said that the Paris killers "are not loyal to any type of divine religions - including Islam".
The Prince of Wales is to send Mr Hollande a message of "profound sympathy and solidarity with the people of Paris", a Clarence House spokeswoman said
Police sources in Paris said around 180 people were injured, including 80 who were in a critical condition.
US officials said that all members of the American rock band Eagles of Death Metal, who were playing a concert at the Bataclan, escaped unhurt.
Scenes of "carnage" were described by witnesses at the Bataclan, who said there was "blood everywhere".
The brother of the band's drummer, Julian Dorio, told the US newspaper Atlanta Journal Constitution that the musicians had hit the floor after seeing gunmen, then fled by a backstage door.
After speaking to his brother by phone, Michael Dorio said: "They saw a man with a machine gun just opening fire."
Television cameraman Charles Pitt said he was outside a cafe in the city's 11th arrondissement where people were shot at around 9.10pm local time.
He told BBC News: "I had literally gone about 30 metres (100ft) when, I thought it was a firecracker to start with, and then it went on and it got louder.
"It went on for a minute. Everybody dived for cover, thinking it was gunfire. Then there was a pause for about 15 seconds and then it all started up again.
"Then it calmed down a bit and I walked back to the front of the cafe and there was a whole pile of bodies, probably about seven on the left-hand side and four that had been sitting on the tables outside on the right-hand side, and a lot of injured.
"I saw a woman who had obviously been shot in the leg."
The Foreign Office advised Britons to "exercise caution in public places" following the attacks, and people with concerns about British friends or relatives in Paris can call 0207 008 1500 for assistance.
French authorities have advised people in Paris to remain in their homes.
Disneyland Paris was closed for the day and all sporting events in the French capital have been postponed, including a rugby union Champions Cup tie involving Scotland's Glasgow Warriors.
Channel Tunnel train operators Eurostar said services would run to Paris, but passengers due to travel on Saturday were being offered a free ticket exchange.
The attacks come after the Charlie Hebdo atrocity in January, which saw 12 people killed after gunmen stormed the Paris offices of the satirical magazine.
They also come a day after Islamic State militant Mohammed Emwazi, known as Jihadi John, was targeted in a US air strike in Syria. It is not clear if there is any link.