Violent clashes broke out in Athens last night on the eighth day of rioting in protest at the police killing of a teenager.

Youths attacked a police station, shops and banks and fought running battles with police, as candlelit vigils were being held to mark a week since the fatal shooting of 15-year-old Alexandros Grigoropoulos.

Several hundred protesters set up burning barricades and attacked police with rocks and flares. Riot police fired teargas and chased the youths through parts of the Greek capital. The protesters chanted "murderers out" and used laser pointers to target officers for attack.

Violence has wracked Greece every day since the death of Grigoropoulos. The protesters are demonstrating against not just the boy's death but at an increasingly unpopular government and mounting economic worries. The riots in cities across the country have left at least 70 people injured. Hundreds of shops have been attacked and looted, and more than 200 people arrested.

While most of the protests have been peaceful, the tone of the demonstrations has been set by a violent fringe, with more young people willing to join such elements than in the past.

Athens remained calm this morning, with no plans for further protests. Traffic returned to normal in the city centre and an open-topped double-decker bus carried tourists round the capital's main sights.

An opinion poll published today in the Kathimerini newspaper found that most Greeks consider the violence as more than a simple reaction to the shooting.

Asked whether the riots constituted a social uprising, 60% responded yes. Sixty-four percent said police were unprepared for the violence.

The protesters promised to remain on the streets until their concerns are addressed.

One protester, 32-year-old Paris Kyriakides, said: "Speaking as an anarchist, we want to create those social conditions that will generate more uprisings and to get more people out in the streets to demand their rights.

"In the end, the violence that we use is minimal in comparison to the violence the system uses, like the banks."