Video: Arrests in Paris gunmen hunt

Photographs of two prime suspects in the Paris attack have been released by police - as a third man handed himself in.

Hamyd Mourad, 18, surrendered to police, after hearing his name on the news in connection with the attack, a judicial official said.

But a massive manhunt for the other two suspects, brothers Said Kouachi and Cherif Kouachi, continues with thousands of police scouring the streets of France for them.

Mr Valls said preventing another attack “is our main concern,” as he explained why authorities released photos of the two men along with a plea for witnesses to come forward.

Twelve people died in the attack on the offices of Charlie Hebdo, a weekly newspaper that had been threatened before for its caricatures of the Prophet Muhammed.

The terror attack has been condemned by global leaders and France’s president Francois Hollande has declared a national day of mourning today following the bloody raid - France’s worst terror attack since 1961.

France has raised its terror alert system to the maximum - Attack Alert - and bolstered security with more than 800 extra soldiers to guard media offices, places of worship and other possible targets.

In the UK, Home Secretary Theresa May will chair a meeting of the Government’s emergency committee Cobra today.

Prime Minister David Cameron has offered the assistance of British spies to help French agencies investigate the atrocity.

Police warned the brothers - French nationals in their 30s with possible links to al Qaida - should be considered armed and dangerous.

By the time Mourad handed himself in to a police station in the Champagne region yesterday evening, heavily armed police had stormed a flat in the city of Reims, east of Paris, searching for the suspects without success.

Twelve people were killed when the masked gunmen armed with Kalashnikovs burst into the magazine’s Paris offices yesterday morning and opened fire indiscriminately.

They shouted “Allahu Akbar” - God is greatest - as they opened fire, killing a number of the publication’s staff and two police officers.

A chilling video captured the pair moments later climbing out of their black car and calmly jogging towards a police officer as he lay injured on the floor, and gunning him down before fleeing.

Eight journalists, two police officers, a maintenance worker and a visitor were killed, said prosecutor Francois Molins.

Another 11 people were wounded, four seriously.

The gunmen are said to have headed straight for the magazine’s editor Stephane “Charb” Charbonnier, killing him and his police bodyguard first.

They then turned their guns on cartoonists Georges Wolinski and Berbard Verlhac, better known as Tignous, and Jean Cabut, known as Cabu.

Also killed were Bernard Maris, an economist who was a contributor to the newspaper, and another policeman.

Survivor and Charlie Hebdo cartoonist Corinne “Coco” Rey told French newspaper L’Humanite she was with her young daughter when the terrorists forced her to punch in the security code to open the magazine’s office door.

She said: “I had gone to collect my daughter from day care and as I arrived in front of the door of the paper’s building two hooded and armed men threatened us.

“They wanted to go inside, to go upstairs. I entered the code.

“They fired on Wolinski, Cabu ... it lasted five minutes ... I sheltered under a desk ... They spoke perfect French ... claimed to be from al Qaida.”

Witnesses at the magazine headquarters described a scene of carnage, with bullet holes and smashed windows.

Gilles Boulanger, who works in the same building, likened the scene to a war zone.

“A neighbour called to warn me that there were armed men in the building and that we had to shut all the doors,” he said.

“And several minutes later there were several shots heard in the building from automatic weapons firing in all directions.

“So then we looked out of the window and saw the shooting was on Boulevard Richard-Lenoir, with the police. It was really upsetting. You’d think it was a war zone.”

The attackers shouted “we have avenged the prophet” after the shooting. No group has yet claimed responsibility for the atrocity.

The slaughter sparked global outrage. Mr Cameron branded it “sickening” while Deputy Prime Minister Nick Clegg said the killings were a “barbaric attack on freedom of speech”.

It has triggered vigils across the world as people flocked to public squares to condemn the attack.

Hundreds filled London’s Trafalgar Square last night, many holding pens, pencils and notebooks in the air to show their solidarity for the murdered journalists and police.

Others held aloft makeshift placards reading “Je suis Charlie” - “I am Charlie”. The phrase has come to represent people’s shock and outrage at the massacre and has been trending on Twitter.

There were similar scenes at Paris’s Place de la Republique and around the world.

Cartoonists posted satirical pictures on Twitter showing their take on the attack in an act of defiance.

One of the suspects in the attack, Cherif Kouachi, was convicted in 2008 of terrorism charges for helping funnel fighters to Iraq’s insurgency and sentenced to 18 months in prison.

Western leaders rallied to show support for France. Mr Cameron said he had offered Mr Hollande “any assistance our intelligence agencies can give” following the “barbaric” raid.

The Queen sent “sincere condolences” to the victims’ relatives.

At a joint press conference with German Chancellor Angela Merkel in Downing Street yesterday, Mr Cameron said that, in a highly unusual move, the two leaders had been briefed on the situation by the British security agencies.

The 10-minute briefing was based on what the intelligence agencies highlighted as the calm, determined and apparently professional way the killers carried out the assault.

The pair also spoke to Mr Hollande from the Prime Minister’s office in No 10, a call Mrs Merkel described as a “very moving moment”.

Defending the right to free speech Mr Cameron said: “We should be very clear this day that these values that we have are not sources of weakness for us, they are sources of strength.”

Mr Charbonnier was included in a 2013 Wanted Dead Or Alive For Crimes Against Islam article in Inspire, a terrorist propaganda magazine published by al Qaida.

Charlie Hebdo’s editor-in-chief Gerard Biard was in London at the time of the attack. He told France Inter: “I don’t understand how people can attack a newspaper with heavy weapons. A newspaper is not a weapon of war.”

He said the magazine had not received threats of violence: “Not to my knowledge, and I don’t think anyone had received them as individuals, because they would have talked about it. There was no particular tension at the moment.”

UK-based French businessman Pierre-Yves Gerbeau said his nation was reeling.

“The whole country is shell-shocked. It is our 7/7,” he told ITV.

“People do not understand, and I think there’s a coming to terms - this obviously raises a lot of questions about French society. But nobody can point fingers. It’s not ‘them and us’. The Muslim religion is the second biggest one in France, and the second guy who got shot - the poor policeman - was a Muslim.”

He said Charlie Hebdo was an institution and the French “all grew up with that irreverence”.

“As a magazine, they were struggling financially. And these people just made them legends forever. People will throw money for this to survive,” he said.