ATHENS, Dec. 7 (Xinhua) -- Greek Prime Minister Costas Karamanlis said on Sunday that those responsible for the death of the 15-year-old boy shot by police in Exarhia district of Athens the night before should expect no leniency from the state.

    In a letter of condolence to the parents of the slain teenager, Karamanlis promised the state would do everything in its power to prevent such a tragedy occurring again.

A petrol bomb explodes in front of police during riots in Athens Dec.  7, 2008. Greek Prime Minister Costas Karamanlis said on Sunday that those responsible for the death of the 15-year-old boy shot by police in Exarhia district of Athens the night before should expect no leniency from the state.  (Xinhua/Reuters Photo) Photo Gallery>>>

    The premier's promise came in the wake of the worst rioting in decades, which swept through Greek cities until the early hours of the morning.

    According to Athens News Agency, self-styled anarchists and youths belonging to far-left militant groups ran rampage throughout the night and again at demonstrations on Sunday afternoon, coming out in force to protest against the killing of the boy.

    The boy was shot during a skirmish between two police officers and a group of about 30 youths belonging to Exarhia's fringe anti-establishment movement that attacked their patrol car on Saturday night. The 15-year-old boy was shot in the chest and died of his injuries shortly after being taken to hospital.

    Regarding the circumstances of the boy's death, Interior Minister Prokopis Pavlopoulos refused to answer questions until the police investigation was completed, particularly the ballistics report that would show how the shooting occurred.

    He stressed that the investigation would not end until all those shown to share in responsibility for what occurred had been punished. The interior minister went on to appeal for calm, asking the public to assist the police in their legitimate function.

    "The police have and will have a defensive function in order to protect the property and the lives of all Greek citizens. It will continue to have this function after this isolated incident. And Iappeal to Greek citizens to help so that there is calm and the legitimate work of the police can yield results," he said.

    The two special guards making up the police patrol that shot the 15-year-old were led before a public prosecutor on Sunday. The officer that fired the shots against the boy was charged with homicide and illegal weapons use, while his partner was charged as an accomplice.

    The two officers must now appear before an examining magistrate, who will set a date when they will present their testimony.

    The two special guards were placed under arrest immediately after the incident when the teenager was shot dead. Also placed on suspension as a result of the incident was the chief of the Exarhia police station, where the two were stationed.

    Cities throughout Greece were licking their wounds and taking stock of the damage on Sunday morning. Central Athens was the scene of chaos on Sunday as buildings, banks, supermarkets, shops and cars were put to the torch by rioters and streets were cordoned off as protestors wreaked havoc and skirmished with police.

    Violence was also reported in the cities of Thessaloniki, Patras, Ioannina and Hania, in incidents that lasted until the early hours of the morning and then resumed during demonstrations held after midday Sunday. Several police stations were attacked during the night and police officers in several cities became the targets of violence, while patrol cars were torched.