ATHENS (AFP) — Riot police on Friday clashed with youths on the seventh day of Athens street protests as Greek Prime Minister Costas Karamanlis dismissed opposition calls to quit. Officers stormed about 100 youths on the sidelines of a rally called by students, who emerged from behind university walls — and beyond the reach of law enforcement — to lead a 4,000-strong march on parliament. The outbreak of stoning and tear gas proved to be the exception amid anger in Athens and Greece’s second city of Thessaloniki over teenager Alexis Grigoropoulos’ killing by a police bullet. But its international impact took a fresh turn, with a human chain formed by elements among about 300 demonstrators — some waving French tricolours — obstructing traffic on the Champs-Elysees in Paris. French authorities had earlier beefed up security at the nearby Greek embassy. Meanwhile, the offices of lawyer Alexis Kougias, representing two policemen awaiting trial over 15-year-old Grigoropoulos’ death last Saturday, were trashed after Kougias said the death “was sadly brought about by an act of God.” Speaking at a European Union summit in Brussels, Karamanlis condemned the worst unrest Greece has seen since the end of military dictatorship in 1974 and said the country should focus on countering the global economic downturn. Hundreds of banks, stores and public buildings have been destroyed, badly damaged by fire or looted in a week of violence mainly involving youths. Statistics show one in four aged 15-24 are officially unemployed. “At this time the country faces a serious financial crisis… a steady hand on the helm is needed to deal with it,” Karamanlis said. “That is my concern, that is the priority of the government, not scenarios about elections and successions,” he added in response to renewed opposition calls to quit. “The compassion with which all of us ought to treat the distress of young people cannot be confused with blind violence, with the activities of extreme elements,” he told Greek reporters on the sidelines of an EU summit. Karamanlis, whose parliamentary majority consists of just one deputy, is already shaken by corruption scandals and opposition to unpopular reforms including deals to privatise a major Greek port and a state airline. A night-time Thessaloniki march saw the offices of the ruling conservatives vandalised before a torrential rainstorm doused protesters’ efforts, an AFP correspondent reported. Students and workers occupying the Athens law faculty also demonstrated mid-evening. Earlier, AFP witnessed truant school students manning a roadblock made out of burning garbage cans on a major route into central Athens and two Greek press photographers, carrying masks to block out tear gas, being attacked for their prized headgear. Yet Athens was undoubtedly edging closer to normal life — firebombing is routine, many Athenians maintain — and similar protests throughout provincial Greece have fallen away. Nevertheless, prominent university campuses — the springboard for the worst of the Athens attacks — remain occupied by students and angry youths claiming a constitutional right of sanctuary. The education ministry said occupied or otherwise closed schools now numbered just 130. On top of the French attacks, Greek embassies in Russia, Italy, Spain and Denmark have also been targeted with related violence breaking out in Germany. Greek protesters say they are striking out against police repression, corrupt politicians and a social system that offers little hope, while the government blames the violence on loosely organised self-styled anarchists. Slogans such as “state killers,” “murderers, you will pay,” “democracy gives arms, cops assassinate” and “silence only shows complicity” are splashed across banners outside the symbolic Athens Polytechnic building. The officer who shot Grigoropoulos says he was defending himself from a gang of youths and killed the boy by accident due to a bullet ricochet. A ballistics report, said to confirm the officer’s deposition, has yet to be released.