By Renee Maltezou and Ingrid Melander
ATHENS (Reuters) - Greek police fired several rounds of teargas to disperse rioting protesters as thousands marched in Athens on Sunday to mark the police killing of a teenager, which unleashed the country's worst riots in decades last year.
Hooded youths broke from the march of more than 3,000 people to smash shop windows and set garbage bins alight. Riot police chased groups of stone-throwing protesters in deserted streets in the centre of the city, filled with tear gas.
Four police officers and two demonstrators were injured, and 80 people were detained, police said.
Greece's new socialist government has deployed more than 6,000 police on Athens streets saying it was determined to avert a repeat of last year's unrest that hit the capital and major cities causing millions of euros of damage.
"We are using teargas on several fronts where youths are damaging stores and setting fire to garbage bins," said a police official, who requested anonymity.
Last year, thousands of people took to the streets and clashed with police hours after the killing of Alexandros Grigoropoulos, destroying shops, attacking public buildings and burning cars, in rampages that went on for weeks.
The running street battles between police and hooded youths turned central Athens into a war zone, freezing business ahead of the holiday period.
The 2008 riots were fuelled by youth discontent with high unemployment and economic hardship. Protesters on Sunday said the government may have changed but not much had improved in their everyday lives.
"It's been a year since police murdered the boy and the government which caused the murder has collapsed but nothing has changed in terms of police brutality," said Panos Garganas, 63, a university employee. "We want more jobs, more education and no more police."
The socialists revealed after winning October 4 elections that Greece was in much worse shape than reported by the defeated conservatives, with the economy in recession for most of 2009, deficits and debt spiralling out of control.
WAVE OF VIOLENCE
Grigoropoulos's death unleashed a renewed wave of leftist guerrilla violence, with groups targeting police stations, businesses and politicians throughout the year. One policeman was shot dead in June by the Rebel Sect group.
Protesters in central Athens unfolded a banner reading "Remember, remember, the 6th of December." Some dressed in black chanted "Policemen, Pigs, Murderers."
Youths climbed on the roof of the Athens university building in central Athens, burnt the Greek flag and replaced it with an anarchist banner.
An evening memorial service was planned later on Sunday in the Exarchia district, where Grigoropoulos was shot dead, and more protests were planned for Monday.
His parents appealed for peace during the demonstrations, saying violence did not honour his memory. Two policemen are facing murder charges for shooting the teenager.
"I don't want to see Athens burning again," his father Vangelis told an Athens newspaper. "This would not honour my child's memory, it would mar it."
Greek police said about 150 foreign anarchists had arrived from Italy, Spain and other European countries. Police arrested 75 youths on Saturday, including 5 Italians and one Spaniard, for carrying wooden sticks or throwing stones at police.
(Writing By Dina Kyriakidou, Editing by Sonya Hepinstall)
