Fresh riots erupt in Greek cities
Thousands of protesters have attacked banks and shops in Athens and the northern city of Thessaloniki, angered by the police's killing of a teenager.
Demonstrators threw firebombs, rocks and other objects at the buildings and at police, who responded with tear gas.
Earlier, Interior Minister Prokopis Pavlopoulos appealed for restraint.
The streets of the capital were already strewn with glass and rubble after a night of rioting sparked by Saturday's shooting, in the Exarchia district.
During the overnight violence, protesters hurled rocks and petrol bombs at the police and damaged dozens of buildings.
In a statement, the police said that Saturday's riots had left 24 police officers injured, one seriously, and 31 shops, nine banks and 25 cars damaged or burned.
Six people were arrested, one of them for carrying a weapon.
Alex Hadjisavvas, the owner of a shop on Patission Avenue, told the BBC that many nearby businesses had also been looted.
"The window was smashed, the shop front damaged and a large quantity of stock taken from inside has been used by the rioters as material to start street fires," he said.
The unrest, the worst in the country in several years, later spread to Thessaloniki and the southern island of Crete.
Police 'powerless'
The BBC's Malcolm Brabant says that after a lull in the fighting on Sunday morning, youths left the Polytechnic college and joined hundreds of others on a march towards the police headquarters on Alexandras avenue.
They passed close to where the teenager, who has been named as 15-year-old Andreas Grigoropoulos, was shot dead on Saturday. One banner they were carrying called the police "murderers".
One protester outside the National Museum told the BBC he had been greatly angered by the actions of the police.
"It's not the first time. They always kill people - immigrants, innocent people - and without any excuse," he said. "They murdered him in cold blood."
"I think [the violence] is justified. Peaceful demonstrations cannot get a solution to the problem... They can feel the pressure from the people and not do it again."
As many expected, the march soon turned violent, with protesters throwing firebombs at riot police after tear gas was fired in an effort to disperse them.
Several banks and shops were attacked, while a supermarket and at least one car dealership were set alight, police and witnesses said. Clashes also broke out near the parliament.
In Thessaloniki, a march by more than 1,000 people on two police stations also descended into violence when protesters threw firebombs at police and attacked nearby shops and banks.
They also damaged vehicles belonging to Greek TV channels.
There have meanwhile been unconfirmed reports that a policeman was injured and banks and cars set on fire during protests in the western city of Patras.
Public anger
Earlier, the country's interior minister called for restraint and expressed sadness over Andreas Grigoropoulos's death.
"It is everyone's right to demonstrate and to advocate for their rights," Mr Pavlopoulos said. "But I stress, not by destroying the property of others, not turning against people who are not to blame for anything."
Both he and Deputy Interior Minister Panagiotis Chinofotis have submitted their resignations, but they were not accepted by Prime Minister Costas Karamanlis.
Mr Karamanlis has publicly apologised to the father of the dead boy.
"I know nothing can relieve your pain, but I assure you... the state will act, as it ought to, so that yesterday's tragedy won't be repeated," he said.
The two police officers involved in the shooting of the teenager have been arrested, and an inquiry is under way.
In a statement, the police said their patrol car had been attacked by about 30 youths throwing stones. They were attacked again and responded, with one firing a stun grenade and the other shooting and fatally wounding the boy.
However, our correspondent says that nothing the politicians or authorities can say or do will reduce the anger that is building.
A similar shooting incident in 1985 led to a lengthy vendetta between the youth and police, with violence continuing for years.
Citizens in major towns and cities across the country are therefore bracing themselves for the worst, he adds.
Violence often breaks out during demonstrations in Greece, but people are rarely injured. Last week, a small group of people clashed with police at a protest against the government's education policy.
Ruddy 'ell, I know some Greeks have a temper on 'em, but it's getting slightly ridiculous now.
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- PeZook
