INTRO: Hundreds of demonstrators have staged violence riots in Greece's two main cities during a second day of protests over the killing of a 15-year-old boy by police.
MOREINFO: Greece's worst riots in years erupted late on Saturday after the shooting in Athens and quickly spread to the northern city of Thessaloniki and other towns. Despite appeals for calm from Greece's conservative government, violence erupted again on Sunday. In Athens, tear gas choked the central Alexandras Avenue and protesters rained petrol bombs down on police, setting fire to buildings.
The Greek government appealed for calm after riots in Athens on Saturday - a day later and this was the response.
Police were bombarded with petrol bombs - at least 24 officers were injured - one of them seriously.
The death of a 15-year-old boy sparked the riots.
He was shot by a police officer after a patrol car was attacked by a group of 30 youths in a volatile part of the city.
Two police officers have been arrested in connection with the death - prosecutors say one will be charged with manslaughter the other with aiding and abetting him.
The action was swift but not enough it seems to curb the anger on the streets.
For a second day Athen's burned.
Dozens of shops, banks and cars were set alight.
And it didn't end in Athens - a protest in the northern city of Thessaloniki also descended into violence.
1,000 demonstrators chanting "Killers in Uniform" lobbed fire bombs at police.
Greece's Prime Minister Costas Karamanlis has publicly apologised to the father of the dead boy.
He said "the state will act" so the "tragedy won't be repeated".
But his conservative government has been rocked by scandal in recent months and his economic woes are many.
One in five Greeks live below the poverty line and there've been numerous strikes and protests.
Socialists have taken the lead in opinion polls.
Many believe this may be the final straw for the Prime Minister - early elections are being predicted for next year.
Sonia Legg, Reuters.