Six minors were among the 13 people arrested by Greek authorities for their involvement in Sunday night's riots, according to ABC News. Hundreds of people attended a march led by anarchists to protest the death of schoolboy Alexandros Grigoropoulos, a 15-year-old killed by police Dec. 6, 2008. His death was the catalyst that led to the worst riots seen in Greece for decades, according to Reuters. The march has been held annually ever since and is typically attended by a large number of anti-austerity protesters.

Towards the end of the march, demonstrators began to throw petrol bombs, bricks and broken marble at riot police, who responded with tear gas and stun grenades, according to Reuters.

More than 6,000 officers had been deployed to deal with the protesters and four were injured during the riots, reported the Huffington Post. The smoke from the tear gas is reported to have combined with burning rubbish and affected a nearby residential area, according to Reuters.

Grigoropoulos was fatally shot seven years ago by Greek police and became a name for young protesters to rally behind, according to the Guardian. The week of rioting that followed his death was intense and devastating, with children as young as 12 reported as having joined the march on the streets, said the Guardian.

Epaminondas Korkoneas, 38, was the officer responsible for shooting Grigoropoulos and was sentenced to life in prison in 2010 after a court in the town of Amfissa declared it intentional, reported BBC News. His patrol partner, Vassilios Saraliotis, 32, was sentenced to 10 years in prison for his part in the incident.

A statement released by police said that those arrested will be charged with a number of offenses, including use of explosives, arson and breach of the peace, according to ABC News.