A third attacker is still on the run after the massacre at Tunisia's Bardo museum which left 23 dead, the country's president has said. President Beji Caid Essebsi said the attack involved 'three aggressors' and the third man escaped, in an interview broadcast on French television. He was speaking live with French network iTele from inside the museum where extremists killed 21 people. Scroll down for video . A third attacker is still on the run after the deadly assault on Tunisia's Bardo museum, the country's president Beji Caid Essebsi has said . The news comes after a video was released of the pair roaming the Bardo, and appearing to 'let go' a visitor . The two attackers encounter a man with a backpack walking down a flight of stairs in the museum - but let the visitor escape with his life before carrying out the deadly attack . he man in the backpack scuttles off as the two armed men prepare to carry out the chilling attack . Suspects have been arrested over the attack but it was previously believed just two gunmen launched the attack on the museum. The news comes after a video was released of the pair roaming the Bardo. The one-minute video posted on the government's Interior Ministry Facebook page shows the two men scurrying through the Tunis museum, carrying assault rifles and bags. One of the attackers is wearing a baseball cap and a heavy jacket, while the other wears a red hooded jumper and tracksuit pants. At one point, they encounter another man with a backpack walking down a flight of stairs. They briefly acknowledge each other and let the unidentified man walk free before unleashing the deadly attack in the country's largest museum. The video also shows stills of the dead gunmen - named as Yassine Laabidi and Hatem Khachnaou - who were killed in a firefight with security forces, including a picture indicating at least one was wearing an explosive belt. Hostages flee the museum during the Tunisian special forces raid which ended in the death of both gunmen . The government now plans to deploy the army to major cities to bolster security following the shootings - here policeman stand outside the Carthage International Airport in Tunis . Police responding to the attack shot and killed the two gunmen. They were identified as Tunisians in their 20s who had trained in Libya. Essebsi said the extremists who have recruited about 3,000 Tunisians to fight in Iraq and Syria have no credible connection to Islamic belief. He said his country was at war with them. 'When war is brought upon us, we will wage war,' he said. ISIS claimed Wednesday's attack on foreign tourists in Tunis, the deadliest involving foreigners in Tunisia since a 2002 suicide bombing on the island of Djerba. Tunisian fighters make up a disproportionately high number of foreign recruits to ISIS in Syria, with as many as 10,000 having signed up. Shattered: The walls and windows were peppered with bullet holes while unused grenades lay scattered among debris . The government said the two gunmen had trained in jihadi camps in Libya before the attack inside the heavily secured Tunisian parliament compound. Among the 23 dead in Wednesday's attack, 17 were cruise ship tourists, including British mother-of-two Sally Adey. They also included a Tunisian policeman. Mrs Adey, 57, from Shropshire, had been on a cruise of the Mediterranean with her husband, Robert, and was on an excursion to the museum. Police in Tunisia have arrested five people described as directly tied to the two gunmen. Four others said to be supporters of the cell were also arrested in central Tunisia, not far from where a group claiming allegiance to al Qaida's North African branch has been active. ISIS issued a statement and audio on jihadi websites applauding the dead gunmen as 'knights' for their 'blessed invasion of one of the dens of infidels and vice in Muslim Tunisia'. As investigations into the massacre continue, Tunisian security officials have been asked why the world-famous museum was completely unprotected. The government now plans to deploy the army to major cities to bolster security following the shootings.
President Beji Caid Essebsi said the attack involved 'three aggressors'
He told French TV station that a third man escaped and was on the run . Was previously believed just two gunmen launched attack on the museum . Deadly terror attack on Wednesday in Tunis museum left 23 people dead .