Britain's Home Secretary Theresa May will chair a meeting of the UK's Cobra group today (8 January) following the terror attack in Paris.
Government ministers, police and security advisers will discuss and co-ordinate the actions of the UK's security services in the wake of the assault on satirical weekly Charlie Hebdo.
French authorities have confirmed that eight journalists and two policemen were among the 12 people killed. David Cameron condemned the murders as a "sickening" attack on press freedom.
"The murders in Paris are sickening. We stand with the French people in the fight against terror and defending the freedom of the press" Cameron said.
Labour leader Ed Miliband joined the Prime Minister in expressing his "horror and outrage" at the events in Paris.
Foreign Secretary Philip Hammond also said he is "appalled" by the attack in Paris. He tweeted: "My thoughts are with the family and friends of those killed."
Crowds flocked to Trafalgar Square in London last night (7 January) to show solidarity with Charlie Hebdo.
Demonstrators carried signs with #JeSuisCharlie (I am Charlie) in support of the murdered journalists.
Paris police said one suspect, Hamyd Mourad, had handed himself in while two other suspects, French nationals Said Kouachi and Cherif Kouachi, were at large.