A protester throws a metal crowd barrier at riot police outside parliament during a demonstration in central Athens, Greece, 12 Dec 2008

Greek youths have hurled rocks and firebombs at riot police in central Athens, as unrest continues for a seventh day following the police shooting of a teenager.

Police Friday fired tear gas and clashed with protesters attempting to march toward parliament.

Police officials say they are urgently seeking more tear gas from Israel and Germany after using more than 4,600 capsules.

Rage over last Saturday's killing has turned into anger over corruption and economic hardship.  The violence has shaken the conservative government of Prime Minister Costas Karamanlis, which has a one-seat majority in parliament.

Mr. Karamanlis today rejected mounting calls for his resignation, saying his priority was to provide the country steady leadership to tackle the financial crisis.

Scores of protesters and police in Athens and the northern city of Salonika have been injured since Saturday, when police gunfire in Athens' central Exarchia district killed the 15-year-old boy.

Protesters continue to occupy several schools and universities Friday.  Others briefly took over an Athens radio station and read a statement on air.  

The two Athens policemen involved in the shooting have been jailed pending trial.  One faces murder charges, while the other is accused of being an accomplice.

The officers say they were only firing warning shots.  Their lawyers say initial forensic analysis shows the boy was hit by a ricochet, and not a direct shot as charged by some witnesses.

Protests have spread beyond Greece's borders, with demonstrations in other European cities, including Barcelona, Berlin, Copenhagen, London, Madrid, Rome and The Hague. 

Some information for this report was provided by AFP, AP and Reuters.