Masked men wielding clubs guard the entrance to the Athens Polytechnic University, keeping watch over the graffiti-covered walls on campus. Nearby streets are barricaded with the carcasses of burnt cars, and a huge black banner proclaims "MURDERERS" – the rallying cry that has brought Greece's youths to the streets. Inside, piles of empty gas canisters testify to the scores of Molotov cocktails assembled there recently For more than a week, Athenian streets have been a battleground between police and protesters, whose anger was sparked by the fatal shooting of a 15-year-old boy by a policeman. Protected by Greece's Constitution from police interference, the Polytechnic has become the headquarters of the protest movement – and a haven for those wreaking havoc on the city's streets.

As Greeks try to make sense of the chaos – and prepare for another week of protests, ranging from sit-ins to nationwide roadblocks – many here are beginning to ask whether the asylum law is protecting free speech or simply harboring criminals.

"The university asylum is for the freedom of movement of ideas, but not of commitment of criminal actions," says George Bergeles, a professor at the Polytechnic who is sympathetic to the students' complaints, but not their harsh tactics. "The law about university asylum I believe is a fantastic achievement of the university movement, but we should protect it by not allowing criminal offenses to happen inside."

The Polytechnic holds historic importance for Greeks. In November 1973, students barricaded themselves inside in rebellion against the country's military junta, which had been in power since 1967. Fearful that the revolt would spread, on Nov. 17 the national police moved in with tanks, killing a still-disputed number of protesters.

The junta fell less than a year later. Greece's new Constitution gave special status to universities and other schools, forever barring the police from entering their grounds.

Today, the Poly-technic and other institutions of learning are once again brimming with revolutionary zeal. Across Athens, high schools and universities are under occupation by students and other youth angry at the Dec. 6 killing of Alexandros Grigoropoulos and also at a political system they see as corrupt and incompetent.

So far, Prime Minister Costas Karamanlis has rejected calls by opposition leaders to hold early elections, but his center-right party holds only a one-seat majority in parliament, and public support for his government was weak even before the riots. The latest poll numbers show a 20 percent approval rating.

The Polytechnic, which lies on the border of the edgy neighborhood of Exarchia, where the 15-year-old was killed, is serving as the heart and brain center of the revolt.

There, anarchists – many of whom call Exarchia their home – are helping to organize students and other young people. The area just outside its gates has been the site of some of the most intense clashes with police. Inside, protesters regroup and rearm around bonfires that burn through the night.

There's an air of menace outside the Polytechnic. But Stergia Sarantopoulou, an architecture student there who has been participating in protests, says the mood is angry but collegial. Like many students, she passionately defends the asylum law.

"There are historical, political, ideological reasons for the immunity to exist," she says. "Universities are our home. It's the students home; it's the teachers home."

The university safe-haven policy might at times be abused, Ms. Sarantopoulou says, but in the long run society is better off by having a law that forever ensures a safe place for free speech.

"It's much more harmful for the state to control [universities,]" she says.

The explosion of rioting and looting that took place in the aftermath of Alexandros's death has faded in recent days, but there are still daily protests, many of which end in hails of rocks and flaming Molotov cocktails. On Saturday, the one-week anniversary of the shooting, the protests were largely peaceful, though still angry.

In daylight, a fragile normality began to return to the city center, with shops again opening and people returning to work. But at night, uncertain Athenians stayed away from the normally bustling city center, which was ghostly quiet. Groups of young people roamed the streets across central Athens, shouting: "This night is for Alexi!"

A heavy cloud of tear gas and smoke hung over Exarchia, which felt like a rebel-held enclave in a city at war. Police lingered warily on its edges as young people set up burning barricades and attacked government buildings and banks. And clashes erupted once again outside the Polytechnic.

Few here think the unrest will end anytime soon, and the rage of Greece's youth continues to smolder. The death of Alexandros's has tapped into anger about a range of broader complaints – about corruption, nepotism, a failing education system, and the poor economic prospects of young people, including unemployment rates in the 25 percent range.

Protests are expected to continue throughout the week, with activists calling for roads to be blocked nationwide on Tuesday. They say they want to bring down Greece's whole political system – it's not just the current government that is seen as tainted, most believe the main opposition is little better. The protesters, however, struggle to articulate exactly what they want in its place.

"Don't bend your head down," they chanted as they confronted police recently in front of parliament. "The only way is resistance."

Material from the Associated Press was used in this report.