Riot police are seen during clashes in Athens' neighborhood of Exarchia, Greece, Dec. 6, 2014. The sixth anniversary of the killing of Greek teen Alexandros Grigoropoulos by police fire was marked on Saturday with a series of protests in Greece which ended in scuffles with anti-riot police in central Athens. Photo:Xinhua

 
Violent clashes between youth and police in a string of marches in Athens and other major cities across Greece marred on Saturday evening the sixth anniversary of the killing of Greek teenager Alexandros Grigoropoulos by police fire.

No serious injuries have been reported from the extensive scuffles which broke at the end of the demonstrations organized by students and Leftist political parties in spite of the strong presence of anti-riot police forces in particular across the Greek capital's centre.

More than 120 individuals have been detained in Athens and other cities for attacking police forces with rocks and fire bombs and causing damages to cars, bank branches, shops, bus stops, phone booths and kiosks police said.

The protests were staged in order to commemorate the death of the 15-year old student at the central Athens district of Exarchia six years ago, as well as to express support this year for one of the victim's close friends, Nikos Romanos, who is on the 27th day of hunger strike.

Romanos, an anarchist who is serving a 16 year sentence for an armed bank robbery after his arrest earlier this year, is on hunger strike over a furlough to study at university. Authorities denied his request amidst concern that he might attempt to escape.

The 21-year old convict is currently hospitalized at a state hospital as the Justice Ministry is examining ways to resolve the matter.

Romanos witnessed the fatal injury of Grigoropoulos by a police man who claimed he fired in self defense when he came under attack by a group of youngsters who were pelting rocks against him and his partner during a patrol.

The police officer was sentenced to life in prison in 2010, but tensions remain high each year on the anniversary of the killing which triggered riots unprecedented in Greece for decades.

For two weeks in December 2008 youth were damaging cars and buildings across the country in protest of "police violence."

On Saturday groups of hooded youth set fire to dumpsters and damaged vehicles and buildings across a three- kilometers zone in central Athens from the site of the killing to Syntagma square in front of the parliament.

The images of violence marred the peaceful demonstrations in which about 12,000 people participated in Athens, according to police estimates.

Similar violent incidents marred smaller protests held in cities from the northern city of Thessaloniki to the port of Patras in western Peloponnese peninsula and the island of Crete in southern Aegean Sea, as it had happened in previous anniversaries.