A bomb exploded Saturday outside an Italian high school named after a slain anti-Mafia prosecutor, killing a student and wounding several others, officials said, and rattling a country already tense over a spate of attacks on government officials and buildings.

The device went off a few minutes before 8 a.m. in the Adriatic port town of Brindisi in the country's south just as students milled outside, chatting and getting ready for class at the mainly all-girls Morvillo-Falcone vocational institute.

The school — which prepares students for jobs in fashion and social services — is named in honor of prosecutor Giovanni Falcone and his wife, Francesca Morvillo, a judge who died with her husband in a 1992 highway bombing in Sicily by the Cosa Nostra.

Mesagne Mayor Franco Scoditti identified the victim as Melissa Bassi, 16, from the town. Brindisi civil protection agency official Fabiano Amati said she died of her wounds after being taken to hospital.

One of the shaken students who witnessed the attack told reporters that one injured girl, her hair charred, screamed the name "Melissa, Melissa" when she realized her friend was gravely injured.

Amati said at least seven other students were hospitalized, but some news reports put the figure at 10. Perrino health director Graziella Di Bella said most of them suffered burns and shrapnel-like wounds, and several had undergone surgery.

"The explosion sent out fragments and flames ... pieces of iron," Di Bella told Sky TG24 TV in an interview. She said a team of four psychologists were working with the students.

"One of the (injured) girls asked me: 'What do we have to do with this?" Di Bella said, adding the students were feeling a sense of "disorientation, terror" as well as anger.

Dr. Paola Ciannamea, a Perrino Hospital physician who helped treat the injured, told reporters that one of them was a teenage girl who was in a grave but stable condition after surgery.

Anti-Mafia prosecutor Cataldo Motta, based in the nearby port of Lecce, told reporters that there had been no claims of responsibility. He added that the bombing didn't appear to be the work of organized crime, since fuel and not dynamite, the Mafia's traditional choice of explosive, was used. Motta said the "international terrorism" angle was unlikely, but stressed that investigators had not ruled out any hypothesis.

Italy has been marking the 20th anniversary of the attack on the Sicilian highway that killed the prosecutor and his wife, but it was unclear if there was an organized crime link to Saturday's explosion.

Interior Minister Anna Maria Cancellieri, in charge of domestic security, said she was "struck" by the fact that the school was named after the slain hero and his wife, but she cautioned that investigators at that point "have no elements" to blame the school attack on organized crime.

"It's not the usual (method) for the Mafia," she told Sky in a phone interview. The Sicilian-based Cosa Nostra usually targets specific figures, such as judges, prosecutors, turncoats or rival mobsters in attacks, and not civilian targets such as schools.

The school bombing is an attack of "unprecedented cruelty," the minister said.

"The big problem now is to get intelligence" on the attack, said Cancellieri. She added that she had spoken by phone with Italian Premier Mario Monti, who is in the United States for the G-8 summit.

Monti's office said that the premier ordered flags flown at half-mast for the next three days. He pledged that the government would work to crack down on crime and to "favor the maximum cohesion of all political and social forces to prevent the return in our country of subversive attacks," a statement said.

National police chief Antonio Manganelli told Sky TG24 in a phone interview that Italy's "best investigators" had been dispatched to Brindisi to determine who was behind the attacks. National anti-Mafia prosecutor Piero Grasso arrived and surveyed the blast scene without making comments to reporters.

Manganelli said there were "shadows" of doubt clouding the hypothesis that the school blast was caused by organized crime because the Sicilian-based Mafia usually targets precise individuals. Still, he said, neither the hypotheses of organized crime nor that of subversives have been ruled out.

Outside the school, textbooks and notebooks, their pages fluttering in the breeze, and a backpack littered the street near where the bomb exploded. At the sound of the blast, students inside the school ran outside to see what had happened.

Officials initially said the bomb was in a trash bin outside the school, but later the Italian news agency ANSA, reporting from Brindisi, said the device had been placed on a low wall ringing the building and near the bin. The wall was damaged and charred from the blast. Sky TG24 said the device included three containers of fuel. It was unclear if the blast was triggered by a remote control or by a timer.

Public high schools in Italy hold classes on Saturday mornings.

The bombing follows a spate of attacks against Italian officials and government or public buildings by a group of anarchists, including the shooting and wounding of an official from a nuclear engineering firm, which is part of a state-controlled company. An anti-nuclear anarchist group that previously had targeted Italy's tax collection agency claimed responsibility for the shooting.

Authorities have said the Italian anarchists have worked in the post in close contact with Greece-based anarchists. Brindisi is a major point of departure for ferries between Italy and Greece, but there was no immediate indication from investigators of any Greek link.

The attacks and threats lodged against authorities prompted the government earlier in the week to assign bodyguards to 550 individuals, and deploy 16,000 law enforcement officers nationwide.

Minister Cancellieri indicated that after the school blast authorities' sense of possible targets had been tested.

"Anything now could be a 'sensitive' target," she said, adding that the "economic crisis doesn't help." Austerity measures, spending cuts and new and higher taxes, all part of Monti's plan to save Italy from succumbing to the debt crisis roiling Greece, have angered many citizens, and social tensions have ratcheted up.

Brindisi is a lively port town in Puglia, the region in the southeastern "heel" of the Italian boot-shaped peninsula. An organized crime syndicate known as the Sacred United Crown has been traditionally active there, but crackdowns have been widely considered by authorities to have lessened the organization's power.

The brother of the slain anti-Mafia prosecutor , Alfredo Morvillo, a prosecutor in Sicily, told reporters in Tuscany at a ceremony to honor his slain sister and brother-in-law that the "Mafia angle is, at the moment, the most credible," ANSA quoted him as saying

"I say that because of the place and the timing," ANSA reported, in reference to both the name of the school and the many memorial services for the 1992 attack that were being held on Saturday.

Brindisi's mayor, Mimmo Consales, noted that an anti-Mafia procession was scheduled for the town in the evening, but added that many such memorial ceremonies were scheduled to be held on Saturday throughout Italy.