Thousands of demonstrators have taken to the streets of Tunis for an anti-terrorism march.
Chanting "Tunisia is free! Terrorism out!", they marched to the Bardo Museum, the scene of an attack in which 21 tourists and a Tunisian died.
French President Francois Hollande and other world leaders attended a ceremony at the museum.
Hours earlier, Tunisian authorities said that they had killed one of the prime suspects in the attack.
Speaking at the museum, Tunisian President Beji Caid Essebsi paid tribute to his citizens' defiance.
"The Tunisian people proved today that they do not bow to terrorism, and that as one man and one woman, they defend the nation. When Tunisia is targeted, the whole nation stands as one."
Gunmen stormed the museum in Tunis on 18 March. British, Japanese, French, Italian and Colombian tourists were among the dead.
On Sunday, President Hollande announced that Huguette Dupeu, a Frenchwoman injured in the attack, had died from her wounds.
As well as the French leader, Italian Prime Minister Matteo Renzi and other foreign dignitaries attended a ceremony at the museum where a stone tablet was dedicated to the memory of the attack victims.
Speaking at the ceremony President Hollande pledged France's support.
"We had four French citizens killed there, victims of terrorism, so it was necessary to participate in this march," he said, adding: "Today it's about Tunisia, and the values it represents in the Arab world and beyond."
Demonstrators waved Tunisian flags and held up slogans of "Not Afraid" and "We Are Bardo" as they marched, surrounded by a heavy security presence.
"Terrorism is an international phenomenon, not a Tunisian one," activist Ben Hazem said. "I think there should be solidarity and unity between us to fight terrorism."
Some leftist political groups chose to boycott the rally. They object to the participation of an Islamist party, who they hold accountable for the rise of Islamic extremism in the country.
Tunisians held a landmark election in December that ushered in a new, largely secular government.
Attack suspect killed
Hours before the march, Tunisian authorities claimed to have killed the alleged leader of the attack, Lokman Abu Sakhra.
He was one of nine armed militants killed in a raid on Saturday, the government says.
A spokesman described him as one of Tunisia's "most dangerous terrorists".
Security officials allege that the militants were members of the Okba Ibn Nafaa Brigade, a jihadist group that has previously claimed deadly attacks against security forces in the country.
A spokesman for the Tunisian prime minister told the BBC that Sakhra, an Algerian citizen, was killed by security forces in the western region of Gafsa.
In the past week, authorities claim to have arrested dozens of people they suspected of links to the museum attack.