At least 14 people were killed and 20 injured Thursday -- most of them tourists -- when an explosion tore through a cafe in the Moroccan city of Marrakesh, the state-run news agency said.
Maghreb Arabe Presse quoted one official as saying that early indications point to a terrorist attack.
Witnesses told CNN the blast occurred at Cafe Argana in Place Jemaa el Fna, the popular bazaar and square that draws thousands of tourists every year.
"We were walking around the souks, right around the corner from Cafe Argana. We heard a gigantic boom, and everyone immediately starting running towards the square to see what happened," according to a German tourist who was about 50 meters from the cafe when the blast occurred.
The woman, who didn't want her name used, told CNN the top floor and terrace of the cafe were "ripped apart" and hundreds of people ran from the area when they realized there was an explosion.
The witness said rescuers were dispatched to the scene and the news agency said police opened an investigation.
It is not immediately known whether the attack was linked to unrest across the Arab world or militant activity, although there have been some protests in Morocco lately.
Thousands of Moroccans held a peaceful demonstration nationwide Sunday, calling for a radical overhaul of the country's governance before a new constitution is unveiled in June by King Mohammed VI.
The march was organized by the Facebook youth movement Fevrier 20. The group said its members would not accept the present draft constitution because it was written by the king's own people. It denounced his decision to refer the new constitution to a committee he appointed.
King Mohammed announced last month he would give up some of his wide-scale powers and make the judiciary independent -- the latter a particularly hot subject in Morocco.
Calls for an end to political detention and questions about the king's personal business activities were also on protesters' banners. There was visible resentment at the royal family's business operations, controlled by its holding company SNI. There were also groups protesting about the prices of basic household items.