Riots and looting erupted across Athens yesterday as the Greek government confronted a sixth day of violent protests over the police killing of a schoolboy.

Demonstrators clashed with security forces outside the country's biggest prison and a university in central Athens while police said groups of youths were reported to be looting stores in various districts. Others blocked main roads.

Formal voluntary homicide charges against the police officer accused of shooting 15-year-old Andreas Grigoro-poulos failed to stem the public anger. Underfire prime minister Costas Karamanlis still left for a European Union summit in Brussels, while

Greek embassies in other countries have also become a target for protests.

A clash at Koyrdallos prison in a western Athens suburb blew up after protesters started throwing rocks and other missiles at police who fired tear gas to force the protesters back, a prison guard said.

The demonstrators were staging a sitdown protest in front of the prison.

Police said there was a second riot at the agriculture university in Athens, which has been occupied by students, and that rampaging youths were looting stores in the Nea Smyrni and Galatsi districts of the capital.

School students also blocked several main roads in Athens.