Reeling from the recent attack on the Bardo Museum, Tunisia is taking measures to tighten its security, including the reinstatement of ousted president Zine Al-Abidine Ben Ali's police chiefs. The terrorist attack on the museum, which is adjacent to the Tunisian parliament in the heart of Tunis, left 23 dead, most of them foreign tourists. Police have been blamed for “failings” that allowed the attackers to slip into the museum armed with machineguns and explosives. But the Tunisian president commended the performance of anti-terror squads that managed to kill two of the perpetrators and thus prevented a worse scene of bloodshed. Tunisian President Beji Caid Essebsi said that a third gunman was involved in the attack. “There were three because they have been identified and filmed on surveillance cameras,” he told Europe 1 Radio. A Tunisian security source said that the third suspect appears to have been involved in planning the attack rather than executing it. The Islamic State (IS), a militant group that has taken over a major chunk of Iraq and Syria, claimed responsibility for the attack. Tunisia's prime minister, Habib Essid, fired police chiefs as part of what appears to be an overhaul of the security apparatus. The heads of police for Tunis and the area surrounding the museum, as well as the director of the tourism police and the chief security officer in the museum itself, all lost their jobs, a government spokesman said. The 18 March attack on this iconic museum is an indication of how vulnerable Tunisia is to assaults by a militant movement that draws logistical support from regional jihadists. Both the assailants, who died in the attack, are believed to have received training in Libya. Tunisia has received praise for its relatively smooth power transition, including legislative and presidential elections that brought Essebsi to power a few months ago. Last year, Tunisian police and army clashed repeatedly with militants in the mountains near the Algeria border, illustrating the perils to Tunisia from jihadists infiltrating the country's borders from both directions. The Tunisian president admitted there were “deficiencies” in the security arrangements in downtown Tunis, but still praised the security unit that responded to the attackers. In an interview published on the Paris Match website last week, Essebsi acknowledged that “police and intelligence didn't exactly coordinate to ensure security at the Bardo Museum.” Essebsi also declared that Tunisia will never be ruled by sharia (Islamic law) and will remain a stronghold of democracy. Islamist Ennahda officials, who are his main partners in the government, may disagree with this view, but for now they are trying not to rock the boat. Security chiefs from the time of Ben Ali are said to have been offered their former jobs, in a bid to reverse the tide of jihadist violence. This trend, if it plays out, ties in with similar developments seen in Egypt and Libya - which saw Arab Spring movements bring down dictatorships - over the past two years. According to the Tunisian newspaper Alchourouk, the attack on the Bardo Museum made the reinstatement of former security chiefs “a popular demand of certain urgency.” But the paper noted that there is “opposition” to this move in political and human rights circles. The IS, which claimed the attack in a voice recording uploaded on jihadist websites, named the two attackers as Abu Zakariya Al-Tunisi and Abu Anas Al-Tunisi, describing them as “knights of the caliphate.” Alchourouk, citing a security source, identified the two attackers as Saber Khachnaou, from the Kasserine Province, and Yassine Labidi, from the Ibn Khaldoun section of Tunis. The Interior Ministry called on the public to provide information leading to the arrest of Maher Al-Qaidi, believed to be the third accomplice in the museum attack. Tunisian authorities arrested more than 20 suspected jihadists, and said that half of them may have been involved in the museum attack.