Anarchists are at the center of much of the violence. But many Greeks  who tend to have a high tolerance for protest  sympathize with the rioters’ criticism of the government. The demonstrations on Wednesday brought out a variety of people, including labor unionists and opponents of the government’s economic policies.

Even those who are taken aback by the violence also express anger at the way the police acted Saturday. It remains unclear exactly what happened, but the police acknowledge that shots were fired in a clash between two officers and a group of youths in Exarchia, where many leftists live and gather. A bullet hit Alexandros Grigoropoulos, 15, who died on his way to the hospital.

“I feel like a relative died,” said Penny Dai, a 17-year-old hairdressing student who was attending a peaceful protest outside the Parliament building on Wednesday evening, in front of the city’s large, charred Christmas tree.

Image Mourners carried the coffin of 15-year-old Alexandros Grigoropoulos during his funeral in Athens on Tuesday. Credit... Oleg Popov/Reuters

Many older Greeks were supportive of the younger ones. Standing outside Parliament on Wednesday, Helen Hathidaki paraphrased the Greek writer Nicholas Kazantzakis, saying, “What happens if the youth don’t resist?”

Ms. Hathidaki said she was protesting because of her unhappiness about the economy. She said she had to take a second job cleaning houses because she could not live on her pension. En route to the large union rally on Wednesday, a history researcher at Athens University who gave her name only as Alexandra said she came out partly because of the economy. But she said she also wanted to protest what she called police brutality.

“I’m against violence, but I can understand what’s happening,” she added, saying that people were angry at the government and worried about the economy, and that the death inflamed those feelings. “It’s like a volcano,” she said, “like an explosion.”