Bulgarian anti-government protesters have rallied peacefully in Sofia for a 41st straight day.

Meanwhile, over 100 politicans and journalists spent the night besieged inside parliament before police evacuated them.

A political crisis that began over utility price rises and spread to accusations that private interests control state institutions has caused months of protests.

The protesters, mostly young and well-educated, are demanding the resignation of the Socialist-led government.

They say it represents a corrupt and discredited political elite, not the nation.

At least 4,000 people joined this evening's rally, chanting "Mafia!" and "Resign!".

They blamed the police for violent scuffles that broke out during the overnight siege of parliament. 

The bitterly divided parliament was closed for business, barricaded and under heavy police guard, but work at the chamber is expected to resume tomorrow in spite of growing pressure on the government to resign.

Politicians were escorted out of the building in police vans at around 3am, more than eight hours after they were trapped inside by protesters who tore up paving stones and piled up garbage bins as makeshift barricades.

Some 20 protesters were treated for head injuries, a hospital official said. Two police officers were also wounded.

Bulgaria's largest trade union, CITUB, called on President Rosen Plevneliev to convene the consultative National Security Council and set a date for early elections before year-end.