TUNIS, Tunisia (AP) -- The radical Islamic State group claimed responsibility Thursday for the attack on a famed Tunis museum that left 23 people dead and scores of tourists wounded, and upended the country's struggling tourism industry.

Defying the extremists, hundreds of Tunisians rallied Thursday at the National Bardo Museum, the site of the attack, stepping around trails of blood and broken glass to proclaim their solidarity with the victims and with Tunisia's fledgling democracy. One person carried a sign saying "Tunisia is bloodied but still standing."

Tunisian security forces arrested nine people, five with alleged direct connections to Wednesday's attack by two gunmen who were later slain by police, the president's office said. The other four suspects arrested in the central part of the country were part of a cell supporting those involved in the attack, the statement said.

Prime Minister Habib Essid told France's RTL radio that Tunisia was working with other countries to learn more about the slain attackers, identified as Yassine Laabidi and Hatem Khachnaoui. He said Laabidi had been flagged to the intelligence agency, although not for "anything special."

The attack was the worst at a tourist site in Tunisia in more than a decade and prompted a leading Italian cruise ship line to announce it was canceling all stops in the North African nation indefinitely.

The deaths of so many tourists will create massive trouble for Tunisia's tourism industry, which attracts thousands of foreigners every year to the country's Mediterranean beaches, desert oases and ancient Roman ruins - and which had just started to recover after years of decline. Two major cruise ships whose passengers were among the victims quickly left the port of Tunis early Thursday, leaving behind grieving family members and slain passengers.

Razor wire ringed the museum entrance Thursday and security forces guarded major thoroughfares in Tunis, the capital.

Culture Minister Latifa Lakhdar gave a defiant press conference in the museum, where blood trails still stained the ground.

"They are targeting knowledge. They are targeting science. They are targeting reason. They are targeting history. They are targeting memory, because all these things mean nothing in their eyes," she told reporters. "There is only their reactionary, very backward and sclerotic ideology."

Later in the afternoon, authorities opened the gates of the museum for a rally in defiance of the bloodshed. About 500 people held a moment of silence amid the shattered glass before singing Tunisia's national anthem.

Participants included black-robed judges and lawyers, families with children and teenagers swathed in the red-and-white Tunisian flag. Many also carried bouquets of flowers for the victims.