ISIL terrorists stormed Tunisia's national museum, killing 17 foreign tourists and two Tunisians yesterday.
At least 21 people in all were killed, including two gunmen, but some attackers may have escaped, authorities said.
It was one of the worst militant attacks in the country that has largely escaped the region's "Arab Spring" turmoil.
Visitors from Italy, Germany, Poland and Spain were among the dead in the assault on the Bardo museum near parliament in central Tunis, prime minister Habib Essid said.
Several other people were reported wounded in the shooting, including three Poles and at least two Italians. The Italian foreign ministry said 100 other Italians had been taken to a secure location. The parliament building was evacuated during the attack. He also said that two or possibly three attackers, remain at large.
Security forces stormed the former palace after two hours, they killed two militants and freed other tourists held hostage inside, a government spokesman said.
One policeman was killed in the police operation.
European Union foreign policy chief Federica Mogherini pinned the blame on Islamic State militants, who have become particularly active in neighbouring Libya. "The EU is determined to mobilise all the tools it has to fully support Tunisia in the fight against terrorism," she added.
Prime minister Essid declared in a national address: "All Tunisians should be united after this attack which was aimed at destroying the Tunisian economy."
Television footage showed dozens of people, including elderly foreigners and one man carrying a child, running for shelter in the compound, covered by security forces aiming rifles into the air. This is the first time that civilians have been directly targeted by an armed group in Tunisia. Until now, terrorists targeted security forces or politicians.
Reacting to the atrocity, Manuel Valls, the French prime minister, said: "We are by the Tunisian government's side." He added: "This terrorist attack...cruelly illustrates the threats confronting us in Europe, in the Mediterranean and in the world."
According to Tunisian state TV, some 150 Tunisian police took part in the operation to kill two assailants and free the hostages.
In a brief telephone conversation with his Tunisian counterpart, Béji Caïd Essebsi, François Hollande, the French president, expressed "France's solidarity with him and the Tunisian people at this very grave time".
Mr Valls, said: "We are condemning this terrorist attack in the strongest terms," after a meeting with European Commission President Jean-Claude Juncker in Brussels.
"We are standing by the Tunisian government. We are very alert about how the situation is evolving," he added.
Some of the Italians at the museum were believed to have been passengers aboard the Costa Fascinosa, a cruise liner making a seven-day trip of the western Mediterranean that had docked in Tunis. Ship owner Costa Crociere confirmed that some of its 3,161 passengers were visiting the capital and that a Bardo tour was on the itinerary, but said it could not confirm if any passengers were in the museum at the time.
The cruise ship recalled all the passengers to the ship and was in touch with local authorities and the Italian foreign ministry. The fact that there are still tourists to attack in Tunisia tells its own story. Ever since it became the birth place of the Arab Spring in 2011, the tiny north African nation has been the only country in the region to enjoy anything approaching stability after the overthrow of its resident dictator.
While Syria, Yemen and neighbouring Libya are now in various stages of meltdown, and Egypt has retreated back into military rule, Tunisia has staged two sets of parliamentary elections, forged a constitution, and moved towards becoming a democracy. However, the process of rebuilding the country after years of iron rule under Zine El Abidine Ben Ali has not been the straightforward process that it once looked like being.
When Tunisians first revolted in January 2011 - following outrage over the death of a fruit vendor, Mohamed Bouazizi, who set himself on fire in despair at harassment by local officials over his lack of a trade permit - it seemed the Arab world was finally showing a new face. The huge crowds who took to the boulevards of Tunis to protest were affluent sophisticated and Western-leaning, and talked not of jihads or Western oppression, but of democracy and human rights of the sort practised in Europe. (© Daily Telegraph London)