The center of Athens looked like a conflict zone last night after almost 24 hours of rioting - probably the worst Greece has seen since the restoration of democracy in 1974 - that was sparked by a police officer shooting dead a 15-year-old boy in the district of Exarchia. Dozens of shops, banks, car dealerships and even an apartment block were attacked, causing millions of euros worth of damage as hundreds of people outraged by the death of the teenager took to the streets. The incident which sparked this reaction occurred at about 9 p.m. on Saturday when two officers were patrolling the area of Exarchia, which is often the scene of clashes between self-styled anarchists and police. Sources said the officers claimed their vehicle was attacked by a group of some 30 people. One officer claims he threw a stun grenade while the other alleges he fired his service revolver three times - twice in the air and once at the ground - in self-defense. One of the bullets struck 15-year-old schoolboy Alexandros Grigoropoulos in the chest, killing him instantly. The officers' version of events is contradicted by several witnesses who spoke to TV and radio. They claim there was simply a verbal exchange between a small group of youngsters and the officers who got out of their car to pursue the youths. The officer, who has not been named, is alleged to have shot at the group, not in the air. The two officers have been arrested on suspicion of murder and illegal use of a weapon. Soon after the incident, Interior Minister Prokopis Pavlopoulos and his deputy Panayiotis Hinofotis tendered their resignations, but they were not accepted by Prime Minister Costas Karamanlis. Pavlopoulos held a news conference yesterday to assure the public that the officers would be punished: «The taking of a life is something that is not excusable in a democracy.» He also said that the police would be «on the defensive» as it focused on protecting property and people's lives. However, owners of dozens of businesses on Athens's main shopping strip, Ermou Street, in Monastiraki, on Alexandras Avenue and in Exarchia, who have suffered serious damage at the hands of rioters are unlikely to have been appeased by the minister's pledge. Last night, as police and rioters played a tear-gas-infused game of cat and mouse around the National Technical University, Pavlopoulos, Hinofotis and Karamanlis met to discuss how the government should deal with this explosive situation. Protests and clashes with officers around Greece The protest march in Athens was replicated in a number of cities, including Thessaloniki, Patras, Ioannina and on Crete, which in many cases led to violent clashes and substantial damage. The most serious incidents occurred in Thessaloniki, where just over 1,000 protesters marched through the city. Some of the demonstrators threw rocks and petrol bombs at City Hall, two police stations, as well as a number of shops and banks. Parked cars were also damaged. In Patras, some 200 people protested in the city center. They threw firebombs at police headquarters and destroyed one patrol car as well as eight other vehicles. One policeman was injured. On Crete, there was unrest in Iraklion, Hania and Rethymnon. In Hania, some 30 people outside police headquarters clashed with officers, who responded with tear gas. In Iraklion, youths went on a rampage through the city, damaging public buildings. A protest in Rethymnon passed off more peacefully.