The French President has declared a national day of mourning tomorrow after 12 people were shot dead in the worst terror attack in Paris for years.
Three gunmen targeted the offices of satirical magazine Charlie Hebdo, and some of France's most famous cartoonists and journalists were murdered.
The publication often printed controversial cartoons featuring the Prophet Mohammed.
President Francois Hollande says they will beat the terrorists by remaining unified.
“France has always overcome its enemies when it was able to really defend its value and we will win because we have the capacity to believe in our destiny. Let us gather together, and long live the Republic and France,” he said.
Kenny: "Shocked and appalled"
Taoiseach Enda Kenny has said he is "shocked and appalled" by the attack on the offices of French satirical publication Charlie Hebdo earlier today, in which 12 were reportedly killed by gunmen.
In a statement released this afternoon, Mr Kenny said "the murder of journalists and writers ... is a direct attack on the basic valued of freedom of speech and of tolerance."
" That this should have happened in a city and a country which for centuries have been leaders in the international struggle for human rights is a particular outrage," he said.
"On behalf of the Irish Government, I offer our total solidarity and support to our French colleagues and friends as they work to capture the perpetrators and bring them to justice," he added.
#OnEstTousCharlie #Rennes #fierté #mobilisation #LiberteDeLaPresse pic.twitter.com/5PRrWdywCB
— Sébastien Sémeril (@semeril) January 7, 2015
Thousands gather this evening in France to protest killings
12 dead, 20 injured
12 people were killed at the headquarters of the French satirical magazine Charlie Hebdo in Paris, say police. 10 journalists are among the 12 dead.
Three masked gunmen stormed the offices of the controversial publication, which has previously been attacked over its portrayal of the Prophet Mohammed.
The attackers were armed with Kalashnikov rifles and are also thought to have had a rocket-propelled grenade during the attack on Wednesday morning.
The bodies of the victims have begun to be removed from the Charlie Hebdo offices as footage showed police officers helping distressed people away from the scene.
The attackers are believed to have called out their victims by name before shooting them. In one video clip, one of them is heard to shout: "We have avenged the prophet."
They are believed to have been let into the building by a female employee who was threatened along with her daughter into putting a security code into a keypad to allow them inside.
A spokeswoman for the Paris prosecutor said the editor and a cartoonist for the satirical newspaper, who went by the pen names Charb and Cabu, were among those killed.
Radio France chief executive Mathieu Gilet announced on Twitter that a contributor, Bernard Maris, was another of the victims.
Two police officers were also among the dead, including one assigned as Charb's bodyguard after death threats were made against him.
Another 20 people have also been injured, at least four seriously. Reports said ambulances were still arriving at the scene of the shooting at 5pm local time.
After the attack, the gunmen returned to their black Citroen getaway car and shouted: "We have avenged the Prophet Mohammed, we have killed Charlie Hebdo."
The vehicle was later found abandoned, and is being examined by forensics teams.
A police official said the gunmen fled towards the eastern Paris suburbs after carjacking another vehicle.
Emmanuel Quemener, a police union representative, said officers were using video technology to try and track the gunmen.
He said: "Those men are our most wanted, so that stays a priority, they're armed and extremely dangerous - and things will certainly evolve behind the scenes."
Shocking footage has emerged of a wounded police officer being shot in the head at point-blank range as he lies on the ground, holding his hands up.
Another video taken from the top of a building near the magazine's offices, shows a firefight in the street below.
One of the gunmen can be heard screaming "Allah", as they level their weapons and a series of gunshots ring out.
A dramatic image has also been published of two men dressed in black standing either side of a vehicle, pointing their weapons at a police car.
Benoit Bringer, a journalist with Agence Premiere Ligne who saw the attack, told the iTele network he saw several masked men armed with machine guns.
Henry Samuel, the Daily Telegraph's Paris correspondent, told Sky News: “According to people on the ground, two masked gunmen burst into the offices very heavily armed, (with) Kalashnikovs, apparently even with a rocket-propelled grenade, and opened fire, leaving several minutes later."
He added: "Then the gunmen escaped and are currently on the run, being pursued.
"They've changed cars. They were in a black (Citroen) DS, now they've taken somebody else's vehicle."
Visiting the scene, Francois Hollande condemned the attack as "an act of barbarism".
An extra 3,000 police officers have been deployed on the streets in a massive security operation as the security threat level in France.
Parisiens have been asked to turn out at 7pm on the Place de la Republique in a show of solidarity with the victims.
Social media users have used the hashtag #jesuischarlie to show solidarity for the victims of the shooting, with the Charlie Hebdo website also using the image as its masthead.
Charlie Hebdo's editor-in-chief Gerard Biard told France Inter: "I don't understand how people can attack a newspaper with heavy weapons. A newspaper is not a weapon of war."
US President Barack Obama and the Russian leader Vladimir Putin have both condemned the shootings.
David Cameron tweeted: "The murders in Paris are sickening. We stand with the French people in the fight against terror and defending the freedom of the press."
The shooting is one of the worst terror attacks in France in decades.
In 1995, a bomb on a commuter train blamed on Algerian extremists killed eight people at the Saint Michel metro station in Paris.
Mohamed Merah, an al Qaeda-inspired gunman, killed seven people in Toulouse in 2012, including three French soldiers and three children.
