Athens  - Hooded youths hurled firebombs at the environment ministry, banks and businesses in more attacks across Athens in the early hours of Sunday after days and nights of civil unrest triggered by the shooting of a 15-year-old boy by police.

Angry youths hurled firebombs at several banks along a busy avenue in central Athens as well as a McDonalds restaurant and two stores of Spanish clothing chain Zara.

The latest unrest followed a candlelit vigil in front of parliament marking a week since 15-year-old Alexandros Grigoropoulos was shot dead by police on December 6 in the Exarchia district of central Athens.

More school students were expected to mobilize in central Athens for further rallies on Monday and throughout the week. Students occupied more than 400 school buildings across the country in protest.

The violence was triggered by the police shooting of a 15-year-old boy on December 6, but students have also been protesting growing corruption and economic and education reforms.

The riots, which have spread to all corners of the country, have been the worst in decades, destroying hundreds of shops, banks, buildings and cars in more than eight cities across Greece, including Athens and the port cities of Thessaloniki and Patras.

Masses of hooded youths and self-styled anarchists have been smashing windows, looting shops and setting up flaming barricades in streets across the country. More than 500 people have been arrested.

Groups of protesters armed with firebombs could be seen battling with riot police in several parts of the capital on Saturday, with police pushing rioters back from the tourist areas of Monastiraki, located in the shaodows of Acropolis.

Within a matter of minutes they managed to bomb large sections of the street including this bank which we are trying to extinguish," said a fireman in front of the burning National Bank of Greece located along Patission Avenue.

Hooded youths, most wearing gas masks, could be seen setting garbage bins of fire and smashing store fronts to the grievance of restaurants which closed early for fear of attacks. Riot police retaliated by firing tear gas.

But even the night-time violence was confined to small sections of the city and was on a much smaller scale than the wide-scale rampage that destroyed hundreds of shops last week.

In contrast to days of violence, hundreds of classmates of the gunned teenager, together with their parents, held a peaceful rally in front of parliament in Athens Saturday.

Huge banners dotted the main square outside parliament, reading "The state kills" and "Down with the government of murderers," where people gathered for days.

The city centre appeared to return to normal, with shops open and cafes filled with customers, after having undergone days of destruction.

Municipal workers could even be seen attempting to decorate the main square of Syntagma for the upcoming festive holidays after a massive tree and Christmas village were damaged by protesters.

Officials said similar rallies were being held elsewhere in Athens and in the northen port city of Thessaloniki and the city of Hania on the southern island of Crete.

The two policemen charged with killing the teenager have been jailed pending trial. He claims he fired warning shots after being attacked by youths in Exarchia, a neighboorhood frequented by leftists and self- styled anarchists.

These posted bulletins around Exarchia asking people to gather in front of Athens main court house on Monday to protest the arrest of their colleagues.

Prime Minister Costas Karamanlis, whose ratings have plummeted over recent months owing to unpopular financial, education and labour reforms, has ignored calls to resign and hold early elections. (dpa)