The centre of Athens was inaccessible Saturday evening after major protest rallies were held by far-Right Golden Dawn (Chryssi Avgi) party members here.
To avert potential violent clashes between demonstrators, police took high security measures and banned marches, Xinhua reported.
Golden Dawn supporters gathered in Syntagma square in front of the Greek parliament, demanding the release from pre-trial custody of the party's leader Nikos Michaloliakos and another two MPs two months ago.
They have been charged with creating and running a criminal organisation following the killing of musician Pavlos Fyssas Sep 18 by a party supporter.
On the other hand, Leftist groups gathered nearby at Monastiraki square and outside Athens University to protest against Golden Dawn.
Attacks have been on the rise in recent months after the party's entrance in parliament in last year's elections amidst peoples' anger at austerity implemented to tackle the Greek debt crisis.
After the murder of two Golden Dawn members by a Leftist group a few weeks ago in retaliation for Fyssas' death, tension is running high and Greek authorities have taken steps to avert further incidents.
According to a statement by Greek police, the marches were not allowed to protest Saturday for reasons of public safety.
