A VIDEO has emerged showing the gunman in the French supermarket siege pledging allegiance to the Islamic State terror group.

In the posthumous clip, Amedy Coulibaly admits his links with the Charlie Hebdo killers and details the planning and reasoning behind the sickening attacks.

The footage shows him displaying a small arsenal of weapons, doing press ups and speaking in broken Arabic as he tells how he and brothers Said and Cherif Kouachi planned the shootings together.

"My brothers, our team divided things in two," he tells the camera in a close-up. "We did things a little bit separately, a little bit together. ... We managed to synchronise."

The video, which emerged as millions took to the streets of Paris to protest against the attacks, appeared on militant websites yesterday and two men who dealt drugs with Coulibaly confirmed his identify.

The Kouachi brothers, who killed 12 people at the Charlie Hebdo offices in Paris, told survivors they were from al Qaida in Yemen, and the terror group claimed responsibility for the attack.

The ties between them and Coulibaly, who shot dead a policewoman and four hostages in the supermarket siege, date back to 2005, long before IS had come into being and well before Said Kouachi is believed to have travelled to Yemen.

Seated calmly alongside an assault rifle, wearing a black jacket and cap, Coulibaly explained why the satirical newspaper Charlie Hebdo and the Jewish store were targeted.

"What we are doing is completely legitimate, given what they are doing," he said. "It has been completely deserved for a long time. You cannot attack us and expect nothing back in return."

Following the massacre at Charlie Hebdo, the Kouachi brothers led police on a chase for two days and were then cornered on Friday at a printing house near Charles de Gaulle Airport.

Within hours, Coulibaly - who had by then already killed a policewoman and attacked a jogger - took over the kosher market in eastern Paris with hostages inside, threatening to kill them all unless police let the Kouachis go.

Coulibaly died when police stormed the building shortly after killing the Kouachi brothers.

His widow, believed to be an accomplice, is still on the run and is believed to have travelled to a Turkish city near the Syrian border. However, Turkish security forces claim all traces of her have now been lost.

After speaking in fluent French in the video at first, Coulibaly goes on to speak in broken Arabic, stumbling over words he cannot pronounce that he seems to be reading from a piece of paper.

He struggles with grammar as he gives his allegiance to the head of the Islamic State group and repeats a pact that other loyalists have used to pledge fealty to the militant group.

He then calls for others to carry out similar attacks.

One fellow drug dealer, from the Paris suburb of Bretigny, said Coulibaly regularly sold marijuana and hashish to high school students, and as recently as a month ago, was still dealing.

Both he and another drug dealer identified Coulibaly as the man in the video.

Five people with ties to the Kouachi brothers detained in connection with the attacks have been released from custody, the Paris prosecutor's spokeswoman said.

Family members of the attackers have been given preliminary charges, but prosecutor's spokeswoman Agnes Thibault-Lecuivre said no one remained in detention over the attacks.

Meanwhile, Spain has urged the EU to re-impose border controls in its "Schengen" zone of open frontiers in order to halt the passage of Islamic fighters returning to Europe from the Middle East. Jorge Fernandez, the Interior Minister, made the call at a session of EU ministers called by France to tighten anti-terrorist cooperation.

The French told US and European officials at the session that more intelligence-sharing was needed after they acknowledged failing to keep watch on the three French-born terrorists.

Mr Fernandez said: "We are going to back border controls and it is possible that as a consequence it will be necessary to modify the Schengen treaty."