Security forces are also mobilising in their search for what the prime minister called a “probable accomplice” to three days of bloodshed around the capital.

Prime Minister Manuel Valls said the search is urgent because “the threat is still present” after the attacks that left 17 people dead — journalists at the satirical newspaper Charlie Hebdo, hostages at a kosher market and three police officers — plus the three attackers, who were killed Friday in nearly simultaneous raids by security forces.

HORRIFIC VIDEO: How the Paris terror attacks were planned

FIGHTING BACK: World leaders arm-in-arm in rallies across Paris

Police security forces ... in place at the Unity rally “Marche Republicaine” in Paris. Picture: AFP Source: AFP

France’s defence minister Jean-Yves Le Drian unveiled the fresh measures after an emergency meeting called by President Francois Hollande as attention turned to preventing a repeat of France’s bloodiest attacks in half a century.

The deployment will begin Tuesday, and will focus on the most sensitive locations, which will include Jewish schools.

Nearly 5,000 security forces and police will protect the 700 Jewish schools in the country.

Security boost ... French Defence Minister Jean-Yves Le Drian flanked by French Army Chief of Staff General Pierre de Villiers, at the Elysee Palace after a security meeting with French President Francois Hollande. Picture: AFP Source: AFP

WIDOW STILL ON THE RUN

The security upgrade comes after the widow of one of the attackers crossed into Syria on Thursday, the day after the Charlie Hebdo massacre, and the same day her husband shot a policewoman to death on the outskirts of Paris, according to Turkey’s foreign minister.

Amedy Coulibaly’s common law wife, Hayat Boumeddienne, 26, is the subject of a global ­manhunt and is believed to have fled to Syria via Turkey.

Mevlut Cavusoglu told the state-run Anadolu Agency that Hayat Boumedienne arrived in Turkey from Madrid on January 2, ahead of the attacks and stayed at a hotel in Istanbul before crossing into Syria.

Wanted ... Hayat Boumedienne, the suspect in the Kosher supermarket attack. Source: AP

Once together ... Hayat Boumeddiene and Amedi Coulibaly. Source: Supplied

The ongoing manhunt for Boumedienne continues after Coulibaly appears to have also used a French jogger as target ­practice before he allegedly shot and killed a rookie ­­policewoman in Paris.

Bullet cases found at the site where a jogger was shot and wounded match the gun found at the scene of a fatal shooting in a supermarket in east Paris two days later, the Paris prosecutor said, citing ballistics tests.

Four hostages died in Friday’s siege on a Jewish supermarket which was orchestrated by Coulibaly, who was killed by police.

The Paris prosecutor said ballistics tests were conducted on five bullet cartridges found at the site where the 32-year old jogger was shot in the Paris suburb of Fontenay-aux-Roses, and on the Tokarev automatic pistol discovered at the supermarket.

The two sites are about 15km apart.

CHILLING VIDEO REVEALS TERROR PLOT

Video has emerged of Coulibaly explaining how the attacks would unfold and police want to find the person who shot and posted the video, which was edited after the attacks were over.

Apparently filmed over ­several days, the video shows the 32-year-old with an arsenal of weapons, exercising and ­explaining the rationale for his planned attacks in Paris.

Harrowing video ... Amedy Coulibaly, who is suspected of killing a policewoman in Montrouge on January 8 and four hostages after seizing a Kosher supermarket in Paris. Picture: AFP Source: Supplied

The video was released on terror websites and was ­designed to coincide with the mass rally on the streets of Paris to condemn the killing of 17 people by Coulibaly and his two extremist associates, brothers Cherif and Said Kouachi.

“My brothers, our team, divided things in two,” he told the camera.

“We did things a bit together and a bit apart, so that it would have more impact.”

The terrorist said he had helped the brothers financially with “a few thousand euros” so they could finish with ­purchases for the operation.

People power ... demonstrators take part in a Unity rally "Marche Republicaine" in Beaucaire, France. Picture: Patrick Aventurier/Getty Images Source: Getty Images

He also spoke in halting Arabic with an Arabic flag popularised by jihadists in the background as he pledged ­allegiance to the Daesh death cult — even though the Kouachis pledged loyalty to al-Qaeda.

“What we are doing is completely legitimate, given what they are doing,” he said of the French press and specifically Charlie Hebdo, which published cartoons depicting the prophet Mohammed.

“We are going to have to determine the conditions in which this video was posted,” said Bernard Petit, the head of the Paris judicial police.

United we stand ... thousands of people wave national flags and hold placards that read "I am Charlie" at the Place de la Nation in Paris. Picture: AP Source: AP

“Obviously we’re going to be interested in any people who received and broadcast this video.”

He said about 400 police investigators were working around the clock on the case.

Valls told BFM television that France is at war against “terrorism, against jihadism, against radical Islam.”

Survivors say the Charlie Hebdo attackers, brothers from Paris, claimed they were from al-Qaeda in Yemen, the group the US considers the most dangerous offshoot of that network.

Global backing ... a child holds a sign reading "I am Charlie" in tribute to the 17 victims of a three-day killing spree in Paris in Colombia. Picture: AFP Source: AFP

In the video, Coulibaly pledges allegiance to the Islamic State group.

But ties among the men date back to at least 2005.

While the Yemeni terror group normally only fights domestically but authorities in Europe and the US are now looking at the prospect of the group ­carrying out more terror attacks in the West.

PRISONERS MOVED TO STOP RADICALISATION

As it emerged that Cherif Kouachi met Coulibaly in prison, Valls said France would move to isolate Islamist detainees from the rest of the prisoner population, so as to prevent jails from being used as a breeding ground for radicals.

This measure “must become widespread” but “it must be done discerningly and intelligently”, he said