In extracts of an exclusive interview with CNN published on the channel’s website on Monday, Essid said the 23-year-old author of the worst extremist attack in Tunisian history may have also received ideological training at a mosque.

“I think he was mainly radicalized online,” Essid told CNN of the man identified as a university student named Seifeddine Rezgui.

ISIS, which swiftly claimed responsibility for Friday’s attack, has a huge online presence, using the most cutting-edge technology and social media strategies to attract fighters.

Disguised as a tourist on a beach near Sousse, south of Tunis, Rezgui pulled out a Kalashnikov assault rifle hidden inside a beach parasol and opened fire on holidaymakers.

Asked whether he believed Rezgui had become radicalized while he was at university, Essid replied: “We cannot establish (that) at this moment, but there is some information that he belonged to an organization, and that he was very, very close to a mosque” that provided ideological training.

Essid also said it was unclear whether Rezgui ever travelled to neighboring chaos-wracked Libya, a popular destination for militants who sign up to IS.

“The circulation between Tunisia and Libya could be done through irregular ways,” he said in English, noting that Rezgui had never used his passport to travel.

Essid said the situation in Libya, which shares a long border with Tunisia, was having a negative impact on his country and urged the international community to help find a solution.

“People are trained (by extremists in Libya) and people come back to Tunisia,” he added.

Meanwhile, Essid vowed the Tunisian government’s response to the attack would respect the country’s laws and institutions.

“Things are completely different, what we did in 2011 is irreversible,” he said, referring to the revolution that overthrew dictator Zine El Abidine ben Ali.