An angry crowd of Bulgarian demonstrators, some throwing eggs and tomatoes, blockaded parliament on Wednesday on the 13th straight day of anti-government protests.
Bulgarian leaders sought to ease tensions in the EU's poorest country but protests continued through the evening, with demonstrators booing the Socialist-backed government and calling for its resignation after less than a month in office.
About 1,000 Bulgarians had gathered outside the parliament building in central Sofia in the morning, shouting "Mafia!" and "Resignation!" and preventing lawmakers from entering the building.
Only 112 out of 240 lawmakers braved it through the protesters, prompting a cancellation of the parliamentary session.
Deputy speaker and Socialist party lawmaker Maya Manolova was pelted after trying to address the angry demonstrators, who prevented MPs from leaving the building.
Over 4,000 demonstrators joined the evening rally, police said, and protesters were planning to blockade the parliament again on Thursday.
Up to 10,000 people have protested every night since June 14 after the controversial appointment of a media mogul as head of a powerful security agency, a move which angered Bulgarians fed up with corruption and cronyism.
Although the appointment has been rescinded and Prime Minister Plamen Oresharski apologised, the demonstrations have widened into protests against the government and politicians in general, who are seen as too easily swayed by corporate interests.
Mass protests forced the previous right-wing government of premier Boyko Borisov to resign in February, triggering elections in May that saw the installation of a Socialist-backed administration headed by the non-partisan Oresharski.
"This instability can continue indefinitely, I am afraid. Of course, we will not be able to work without parliament," Oresharski told journalists, while President Rosen Plevneliev urged protesters to remain peaceful.
In a special address, parliamentary speaker Mihail Mikov lashed out at the "aggression against parliament unseen in years".
"The situation in Sofia escalated today, creating anxiety in the whole country... Unlike the peacefully protesting people over the past days, today a relatively small group took part in violent affrays outside parliament," Mikov said.
"We are unable to perform the duties we were chosen for by the Bulgarian people," he said, urging all institutions to help restore peace and enable parliament to push through urgent legislation, including changes to the electoral code demanded by protesters.
"Without respect for the vote of the people, constitutional order and the institutions, a democratic way out of the crisis is impossible, even if snap elections are called," Mikov warned.
The Socialists and their partners, the Turkish minority MRF party, have 120 MPs but in order to function the government needs at least one more lawmaker from the unpredictable ultra-nationalist Ataka movement.
Borisov's opposition conservative GERB party has boycotted parliamentary sessions since last week.
"If Ataka refuses to take part in the work of parliament, this will change the situation towards snap elections," Socialist leader Sergey Stanishev said.
Ataka has repeatedly said it was against a new snap vote but it was unclear if it would return to parliament on Thursday.
Analysts have warned that new elections under the same rules risked returning the same fragmented parliament and exacerbating the crisis.