Andrew Parker, director general of UK security service MI5, says Wednesday's attack at the offices of Charlie Hebdo magazine in Paris is a "terrible reminder of the intentions of those who wish us harm", adding: "As you would expect, we are offering our French colleagues our full support as they respond."

@FaizanAdze tweets, external: The world was sleeping when the sentiments of 1.6 Billion Muslims were hurt and now everyone is coming to show sympathy. #CharlieHebdo

Image source, AFP

French newspaper Le Parisien has given more details about Cherif Kouachi, one of the suspects being hunted by police. According to the paper, Kouachi's past arrest on terror changes was a relief, as he was a "frightened" young man with no real commitment to radical Islam. He remained in custody until his trial in 2008, when he began to change, according to his then lawyer. Vincent Ollivier describes his client looking "withdrawn... he was not himself." Mr Ollivier goes onto wonder if jail had created "time bombs".

Damian Grammaticas
BBC correspondent

During his news piece outside the petrol station which is reported to have been robbed by the two main suspects in the Charlie Hebdon attack, our correspondent says he has seen armed police along the main roads into Paris and military helicopters flying overhead.

David Heal emails: My wife and I have just come from a two minutes' silence outside the Mairie in our village. Most of the inhabitants were there. Even the bar closed. These idiots have shot themselves in the foot... France is boiling over, and interestingly, not against Muslims as such so far, but against terrorists.

Image source, Vishwajyoti Ghosh

Indian cartoonist Vishwajyoti Ghosh was friends with some of the Charlie Hebdo staff killed on Wednesday. He recalls a memorable day spent at the paper: "After some time, Cabu (one of the cartoonists killed) turned to me and said: 'Why don't you draw and put them up? Let's see if your humour's French enough.' I smiled and drew a few things - whether they were French enough I never found out, although they were all very welcoming.

The lawyer for Charlie Hebdo, Richard Malka, tells AFP news agency that next week's edition of the magazine will have a print run of one million - it normally prints 60,000. It will also be half the length at eight pages.

Image source, AFP

Tributes have continued to flood in for those killed in Wednesday's attack, including this picture taken outside the city hall in Toulouse of Stephane Charbonnier - the editor of the French magazine Charlie Hebdo. He was among four cartoonists killed in the attack. The picture also shows a quote from Mr Charbonnier which says: "I am not afraid of retaliation. I don't have kids, no wife, no car, no loan. This can sounds bombastic but I would rather die standing than live on my knees." Read a full obituary about Mr Charbonnier here.

Image source, @emilie_baujard

This is the petrol station north-east of Paris reportedly robbed by the two suspects.

Damian Grammaticas
BBC News

tweets, external: Armed French police now guarding road junctions close to petrol station where #CharlieHebdo suspects sighted this morning

Carole Walker
Political correspondent, BBC News

Speaking in Manchester, Prime Minister David Cameron says the UK will do everything possible to help hunt down and find the attackers. He says "they must be found, confronted and punished". He says the attackers want to disrupt our way of life in free countries and adds "we must not let them do that".

Image source, Pure Evil and Bunny

Drawing sent in by "Pure Evil and Bunny".

Joseph Phan in San Francisco, USA emails: France, stay strong. If you allow this barbaric event to breed even an ounce of hatred, fear, resentment or any ill feeling towards the Muslim community, then the terrorist have succeeded. The men that committed these crimes do not represent any religion - they are only representatives of ignorance.

Peter Hamblin emails: These terrorists should be reminded of the prophetic words used by Admiral Yamamoto after the Pearl Harbour attack...."I fear all we have done is to awaken a sleeping giant and fill him with a terrible resolve."

@UNYouthSA tweets, external: I am Charlie. You are Charlie. He is Charlie. They are Charlie. We all are Charlie. #JeSuisCharlie

A No 10 spokeswoman says the UK prime minister believes it is vital to "stand up for our values, democracy, freedom of speech, freedom of expressions and religion". She also says the PM believes the terror attacks were carried out by Islamist extremists and nothing to do with Islam. "This is an extremist element. This is not Islam," said the spokeswoman.

Norman Smith
BBC Assistant Political Editor

Downing Street say in particular there will be a stronger British security presence at Calais and Gare du Nord. No 10 also says the increased security will involve more searches of trucks and cars at ferry ports, together with additional scanning of freight lorries. An additional police officer has also been sent to join the UK's existing counter terror team in Paris. The British security services are liaising closely with their French counterparts but its understood there has been no request by the French for any direct additional assistance. No 10 say so far there is no evidence that the terrorists have any ties to the UK.

They are said to have driven off in the direction of Paris in a Renault Clio car, apparently the same vehicle hijacked in Paris soon after the Charlie Hebdo attack. According to French commercial channel BFMTV, police are monitoring all of the main entry roads into the capital.

The two main suspects in the attack on Charlie Hebdo magazine in Paris are said to have robbed a service station in the north of France. They stole food and petrol, firing shots as they struck at the roadside stop near Villers-Cotterets, in the Aisne region, French media report.

Despite increased security at UK border points, Downing Street says there is "no specific threat" to the UK.