Six Tunisian police chiefs have been sacked following the terror attack on the capital's Bardo Museum in which 23 people were killed by gunmen.

The police chiefs of Tunis and the officer responsible for security at the museum were among those sacked, a spokesman for Tunisian prime minister Habib Essid told AFP.

"He visited [the area around the museum] last night and saw several deficiencies," Essid's communications director, Mofdi Mssedi, told the news agency.

Of those killed, 19 were foreign tourists. Police have so far arrested 20 people in connection with the attacks, 10 of whom are alleged to be directly involved.

Isis has claimed responsibility for the attack, with Tunisian authorities claiming that the gunmen responsible for the massacre trained at militant camps in Libya.

As security services attempt to stem the flow of fighters travelling to fight for Islamic State in Libya, Syria and Iraq, hundreds of suspected militants have been arrested across the country and alleged recruitment cells broken up, police said on Friday.

On Sunday, President Beji Caid Essebsi said one attacker was still at large.

"There were certainly three attackers... there is one who is on the run. He won't get far," said Essebsi.

In a video of the attackers released by authorities, three men are seen moving around the marble halls of the museum.