ATHENS, Greece (CNN).
(...)A police spokesman said the situation was more contained Thursday than it has been since the weekend, when the police shooting of a teenager kicked off days of riots in Athens and across Greece.
"Of course there are sporadic clashes between students and police officials, but things are a scale or two lower than they were yesterday," police spokesman Panayiotes Stathis said. "There is a gradual deescalation and that's how we hope the situation will proceed."
Hundreds of students have refused to return to school and several of them protested Thursday at local police precincts. Several student groups staged sit-ins along 10 major streets in Athens, at 120 high schools across the country, and at 15 universities.
Students planned a protest for Friday in the center of Athens. Student unions in universities and high schools met throughout the day Thursday to decide their course of action for the coming days.
At the Athens Polytechnic University -- a major flashpoint with clashes between anarchists and police -- municipal crews were able to clear the streets for the first time in days. So much debris was in the streets from the protests that in some places it was half a foot deep.
Anarchists stopped the crews from clearing two streets and taking away burned-out vehicles, saying they wanted to use the cars for barricades in what they said would be street fights Thursday night.

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The only major clash Thursday was outside the large Koyrdallos prison in Athens, where youths faced off violently with police.
Shopkeepers and businessmen seemed determined to reclaim their city from the protesters who have wreaked havoc and caused destruction across Athens. Since Wednesday, groups of merchants have been seen confronting hooded, masked youths involved in the protests, and even fighting with them.
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The violence began Saturday after police officers fatally shot a 15-year-old boy who had been throwing stones at their patrol car along with other youths.
The riots and protests soon became an outlet for simmering anger about the Greek economy, education, and jobs. The events are threatening the government's hold on power, with some opposition groups calling for fresh elections.
The two officers involved in Saturday's shooting were remanded into custody Wednesday pending trial. One is charged with premeditated manslaughter and the other with acting as an accomplice.
Their lawyer said Thursday that initial results from a ballistics test show the officer did not fire directly at the teen. Instead, the bullet ricocheted off another object before hitting the boy in the chest, attorney Alexis Kougias said.
The initial examination shows the bullet taken from the victim was scraped and deformed on one side, Kougias said. That indicates the bullet was one of two warning shots fired by police into the air, which then ricocheted and hit the boy.
Kougias said reports Wednesday that the ballistics test confirmed the ricochet theory were incorrect. The official report is expected later Thursday or on Friday.
Officials fear that if the ricochet theory pans out, it could inflame tensions and spark more riots.