The spirit of protest continued to burn strong in Athens yesterday, as masked youths firebombed the city's riot police headquarters and a group of demonstrators overran a state television studio and appealed to viewers to join anti-government demonstrations. Early in the afternoon, a group of youths emerged from the university complex in Zografou and attacked the nearby riot police station with firebombs. A police officer was injured and six vehicles burnt. Meanwhile in northeastern Athens, a group of around 30 protesters forced their way into the headquarters of state broadcaster ERT and interrupted a news broadcast featuring Prime Minister Costas Karamanlis. For about a minute, the protesters stood in front of the camera holding banners reading «Stop watching, get out into the streets.» ERT Chairman Christos Panagopoulos tendered his resignation over the incident but it was rejected by the government. «It is unacceptable for unidentified individuals to deprive others of their right to information,» he said. Discontent was also simmering in the education sector, with 600 schools and dozens of university faculties under occupation by protesting students. Students are expected to join a rally due to start in Omonia Square at 6 p.m. today and another march is due tomorrow. Meanwhile, sources told Kathimerini that the results of a ballistics test on the bullet that killed 15-year-old Alexis Grigoropoulos, triggering the riots, appear to contradict the claims made by the policeman charged with the boy's death. The results, to be published today, indicate that the officer had fired with his arm at a right angle to his body in the direction of the child, not straight above his head in a warning shot, as he has claimed.