ATHENS (Reuters) - Protesters hung banners from the Acropolis in Greece on Wednesday and called for demonstrations across Europe, in the 12th day of unrest since police shot dead a teenager.

“Resistance” read one of two pink banners in Greek, German, Spanish, and English, which protesters unfurled from the stone wall of the ancient hilltop citadel in Athens. “Thursday, 18/12 demonstrations in all Europe,” said another.

Greece’s worst protests in decades, sparked by the shooting of 15-year-old Alexandros Grigoropoulos, have fed on simmering anger at high youth unemployment and the world economic crisis.

“We chose this monument to democracy, this global monument, to proclaim our resistance to state violence and demand rights in education and work,” one protester, who declined to give his name, told Reuters. “(We did it) to send a message globally and to all Europe.”

The demonstrations have sparked sympathy protests from Moscow to Madrid and European policymakers, including French President Nicolas Sarkozy, have expressed concern they might spread as the economic downturn bites and unemployment rises.

Greece’s powerful industrialists’ union SEV called for a strong government after Prime Minister Costas Karamanlis, whose conservative party is trailing in opinion polls, came under fire for his hands off reaction to the riots.

“The economic turmoil is here and will worsen in the following months,” SEV president Dimitris Daskalopoulos said, “The country needs a strong, credible and modern government.”

Protesters hold a banner at the hill of the Acropolis in front of the Parthenon in Athens December 17, 2008. REUTERS/Yiorgos Karahalis

MORE PROTESTS

About two thousand leftists marched through Athens on Wednesday, chanting “No sacrifice for the rich.”

Others occupied the headquarters of the GSEE private sector union federation demanding the release of those arrested in the riots but the intensity of the protests cooled off this week.

Hundreds of shops and cars were wrecked in 10 cities during last week’s violence. An estimated 565 shops were damaged in Athens alone, costing 200 million euros and causing more than 1 billion in lost sales during the Christmas shopping period.

The protests have rocked the conservative government, which has a one seat majority, and have driven Greek bond spreads -- a measure of perceived investment risk -- to record levels above German benchmark bonds.

The tourism minister said Greece needed to urgently restore its image.

“With the 2004 Olympics we proved we are a civilized, safe country. After the latest events, this has come into doubt,” said Aris Spiliotopoulos.

Protesters hurled firebombs at a police bus in Athens and another group smashed television sets to protest at the media’s coverage of the events. On Tuesday, about 20 students occupied state TV, interrupting a news broadcast to hold up protest banners.

More protests were expected on Thursday, when the ADEDY public sector workers federation goes on a three-hour work stoppage against government policy and the teenager’s killing.

The walkout will ground all but emergency flights into Greece between 1000 and 1300 GMT, air traffic controllers said, and disrupt urban public transport services.

The policeman who shot Grigoropoulos has been charged with murder and jailed pending trial, while his partner was charged as an accomplice. He says he fired a warning shot in self-defense against a group of youths but the family’s lawyer says he aimed to kill without significant provocation.