Athens  - Hooded youths firebombed banks, the offices of the Environment Ministry and businesses in attacks late Saturday across Athens in the eighth day of civil unrest since the fatal shooting of a 15-year-old boy by police.

Youths hurled firebombs at the two banks in cental Athens as well as a McDonald's restaurant and two clothing shops belonging to the Spanish firm Zara and the offices of the Greek Environment Ministry, causing extensive damage.

Youths rampaged in the northern city of Thessaloniki earlier Saturday evening, causing extensive damage to businesses.

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

Gangs of hooded youths and self-styled anarchists have been smashing windows, looting shops and setting up flaming barricades in streets across the country.

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

In contrast to a week of violence, thousands gathered in peaceful demonstrations Saturday across Greece, with hundreds of candles illuminating in a peaceful sit-down demonstration in Synatagma Square before outside the Greek Parliament.

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

Municipal workers could even be seen attempting to decorate the main Syntagma Square for the upcoming holidays, after a massive tree and Christmas village were damaged and torched by rioters.

On Friday, students clashed with police in Athens. More students were expected to rally again Monday in central Athens. Students had occupied more than 400 school buildings across the country in protest.

Although police have reacted when attacked by firebombs, they have held back when youths turned their rage against buildings and cars.

A gang of hooded youths on Friday even pushed their way into and caused severe damage to the offices of Alexis Cougias, the defence lawyer for the police officer accused of shooting the 15-year-old. No injures were reported.

Many countries have issued warnings not to travel to Greece while the popular sites of Plaka and Monastiraki, located in the shadows of the Acropolis, were eerily empty of tourists.

Officials said that tourism was off by 50 per cent. The Acropolis itself was closed due to striking workers. (dpa)