Demonstrations commemorating the second anniversary of the murder of teenager Alexis Grigoropoulos by police in 2008 brought Athens and several other major cities to a standstill on Monday.

People gathered  at the spot where Alexis Grigoropoulos was killed and paid their respects by standing in silence. Many left flowers or candles by a marble plaque which read:”To the memory of young Alexis, he was only 15.”

His mother, Gina Tsalikian, made a rare media appearance on Monday, telling public broadcaster NET TV: “Children should not live in fear and suspicion. The state must assume its responsibility and protect the children, so no other child suffers the fate of my son.”

The two separate demonstration held in Athens were both marred by outbreaks of violence.

Thousands of police officers were mobilized to avert a repeat of unprecedented rioting two years ago as around 6,000 schoolchildren, members of leftist organizations and unionists took to the streets.

Three people were injured and rushed to hospital for first aid during incidents between police and protesters outside the gates of the Athens University (Propylea).

Police said the three injured were a man beaten by youths who suspected him of being a plain-clothes police officer, a woman suffering from shock after a flare exploded next to her at the junction of Ippokratous and Panepistimiou streets and a man found injured in unknown circumstances on the corner of Aiolou and Stadiou streets.

The march from the university gates to Parliament was marred by violence, following an earlier rally by teachers, students and school pupils against the teenager’s killing.

Several hundred hooded youths threw firebombs, stones and bitter oranges at police in full riot gear, who returned with several rounds of teargas and percussion bombs. Protesters damaged bus stops and set fire to garbage cans.

Police helicopters hovered overhead as teargas choked the city centre.

Small-scale outbreaks of violence were also reported during similar demonstrations in other major cities including Thessaloniki and the Cretan port of Hania.