Students, actors, university professors, and many others demanded on Tuesday evening that the immunity of Volen Siderov, the leader of Ataka party, be revoked to pave the way for criminal prosecution.

Some reports suggest the crowd numbered more than a 1000 people.

It followed two incidents, on Friday and Sunday, when the party leader broke into the National Academy for Theater and Film Arts (NATFA), disrupting classes.

On Sunday, his actions, which resulted in police taking him out of the building and shielding him from an angry crowd of students, ended in a fracas, with a man punching Siderov in the face. The lawmakers and party leader had then explained he was looking for a person inside the building who had hit him. After the incident, however, he complained of "police violence" and declared an attempt had been made on his life.

Protesters rallied along some of the main streets in Sofia's central area, including G. S. Rakovski Street, where the NATFA is located and where the scandals involving Siderov took place last week.

"No immunity", "We demand morality!" they chanted after reaching the building, escorted by more than 200 police officers.

An attempt was then made by some demonstrators at reaching Ataka's party headquarters - also located up Rakovski Street, put police had sealed off the area.

On Monday, Chief Prosecutor Sotir Tsatsarov submitted to Parliament a request that Siderov's immunity be lifted to allow for another case of criminal proceedings to be launched, but also to enable his detention. (His demand is in relation to the Friday intrusion of Siderov into NATFA, and not to the developments of Sunday).

Hours later, Parliament Speaker Tsetska Tsacheva said at a press conference MPs were beginning consultations that would change the constitutions by dropping some of the immunity arrangements that are in force for lawmakers.

His Ataka party, which is still described as "far right" by a number of political scientists (and by media outlets), has been facing mounting allegations over the past several years of being a de-facto political arm of the Russian government and serving as a spokesperson for the Kremlin.

Siderov, for his part, does not conceal his sympathy for Moscow and his calls for Bulgaria's withdrawal from NATO and, possibly, the EU.