Several thousand people, mainly students and teachers, assembled outside the University of Athens and marched towards parliament, chanting, "Blood demands vengeance" and "One underground, a thousand in the street." The protest was headed by a banner reading, "Killer State."

Roads were cordoned off around the parliament, which was protected by thousands of police. Youth threw firebombs and stones at police, who fired back teargas before the start of the demonstration near Syntagma Square. Riot police attacked a group of around 100, seizing several and wrestling them to the ground, according to Agence France-Presse. Stun grenades were also fired.

Protesters also entered the National Bank of Greece's main branch and staff fled the building. Demonstrators briefly occupied a private radio station in Athens, reading a statement on air, and a municipal building in the northwestern city of Ioannina.

Another rally took place in Greece's second largest city of Thessaloniki.

Reports state that the police are running out of teargas after using some 4,600 capsules in the last week and have approached Germany and Israel for urgent supplies. The violence employed against demonstrators is such that parents and other adults have had to stand between protesting youth and baton-wielding police.

The previous day, youth clashed with police outside the Exarchia district's Athens Polytechnic, where Grigoropoulos was shot dead. The poly has been occupied since Monday. Students staged sit-ins at 120 high schools and 15 universities nationally and blocked 10 major streets in the capital.

A 24-hour general strike on December 10 against Prime Minister Costas Karamanlis's austerity budget and €28 billion handout to the banks also became a focus for anti-government sentiment. Protesters shouted "Sack Karamanlis" as over a thousand police surrounded the parliament building. That same day, police officer Epaminondas Korkoneas was charged with voluntary homicide and illegal use of his service weapon and Vassilios Saraliotis was charged as an accomplice.

There was widespread anger over Korkoneas's failure to express regret over the killing, with the Ethnos newspaper describing his lack of remorse as "pouring petrol on the flames."

Outside the court, petrol bombs were hurled as the officers' lawyer, Alexis Kouyais, spoke to reporters. Kouyais's denunciations of Grigoropoulos as a "hooligan" who had been kicked out of school were condemned by the Athens Bar Association (DSA) as "slanderous and counter to the lawyers' code of ethics." The student's former school has rejected the claim.

"Slandering the dead 15-year-old, either personally or through repetition of the views of his client to the mass media, as well as the defamation of the lawyers who did not accept to undertake the defence, is a contravention of the rules of deontology in the practice of law and the duty of a direct manner of defence. It comprises a new—ethical—murder that fuels the tension in these days when the entire Greek society is rising up and demonstrating, in tribute to his memory and against police arbitrariness," the DSA wrote. Kouyais now faces the threat of dismissal.

The Korydallos prison, where the two officers are detained, was besieged by high school students. Thousands of students marched towards police stations at Patissia, Glyfada, Ilioupolis, Korydallos, Melissia and other areas of Athens. At least 10 cities have been hit by protests.

There have also been a series of solidarity protests throughout Europe. There are reports of demonstrations in more than 20 countries. Greeks protested in Paris, Berlin, London, Rome, The Hague, Moscow, New York, Italy and Cyprus. According to Reuters, protesters in Spain, Denmark and Italy "smashed shop windows, pelted police with bottles and attacked banks." There were 11 arrests in Spain and 62 in Copenhagen.

Karamanlis, who has only a single seat majority, has rejected calls for his resignation and early elections. On Friday, he insisted that in time of crisis the country required a steady hand.

"That is my concern and the concern and the priority of the government, and not scenarios about elections and successions," he told reporters while attending the European Union summit in Brussels. He denounced "blind violence" and "the activities of extreme elements."

The BBC reported, "Correspondents say the government may impose a state of emergency to bring an end to the violence, but that there is no question of troops being called in."

So deep is the anger over the young boy's killing that, in a parliamentary discussion, Interior Minister Prokopis Pavlopoulos acknowledged what he called a "murderous act" and promised that "justice will be served." But he went on to defend the police and threaten retribution against the protesters.

"Isolated incidents, no matter how heinous, cannot mar the image of police acting within the framework of legality," he said, and warned that "the enemies of democracy will not remain under a hood for much longer. We show no tolerance and never will."

The New Democracy government was facing questions from opposition Communist Party of Greece (KKE) MP Spyros Halvatzis and Radical Left Coalition (SYRIZA) Parliamentary Group Leader Alekos Alavanos, both of whom solidarised themselves with Pavlopoulos's condemnation of violent protest. Halvatzis said that many of those participating in the riots were not students, while Alavanos said his party "condemns violence" and has called only for the democratic reorganization of the police.

Everything possible is being done by the opposition parties, led by the Panhellenic Socialist Movement (PASOK), as well as the trade unions to isolate the students and youth and thereby restore order. But none have acted as strenuously as the Communist Party. It has taken up the accusations by the right wing that SYRIZA, which includes former euro-Communists who split from the KKE and various radical groupings, supports violence.

Yesterday's demonstration was called on the basis of a common statement of "anti-capitalist left organizations" saluting "the demonstrations against the government of murderers all over Greece" and denouncing police repression under the slogan of all such protests: "Down with this government of murderers and thieves!"

The hard-line Stalinists of the Communist Party have accused all those taking part of providing cover for "the provocateurs" and have been congratulated by Employment Minister Fani Palli-Petralia for their "responsible" attitude. The KKE's own demonstrations have urged efforts to preserve "social peace" against the "ultra-left" and "anarchists." The KKE's youth organization has reportedly taken positions inside and outside university faculties, trying to prohibit students involved in protests and occupations from assembling.