"There were failures" which meant that "the police and intelligence were not systematic enough to ensure the safety of the museum", Essebsi told the weekly Paris Match yesterday.
Twenty-one people, all but one of them foreign tourists, were killed when two gunmen stormed the National Bardo Museum in the capital Tunis on Wednesday, in an attack claimed by Islamic State jihadists.
Essebsi however stressed that the country's security forces "responded very effectively to quickly put an end to the attack at the Bardo, certainly preventing dozens more deaths if the terrorists had been able to set off their suicide belts", he was quoted as saying on the Paris Match website.
"I found out there were only four policemen on security duty around the parliament (compound), two of whom were at the cafe. The third was having a snack and the fourth hadn't turned up," deputy speaker Abdelfattah Mourou told AFP.