Tens of thousands of people have taken to the streets across Bulgaria to protest against corruption and the country's rising cost of living.
The demonstrations on Sunday come a week after nationwide demonstrations forced the conservative government to resign.
More than 10,000 protesters marched in downtown Sofia under the slogan "End to illusions, civil action every day!"
They shouted "Mafia!" and "All parties out!" near parliament and the presidency, waving white-green-and-red Bulgarian flags.
Rosen Pleveliev, the president of Bulgaria, appeared briefly before the crowd but was greeted with boos and jeers.
He said he was willing to meet next week with trade unions and civil groups to hear their demands and seek a way out of the crisis that forced the resignation of Boyko Borisov, the former prime minister, on Wednesday.
Borisov's surprise resignation came after demonstrations turned violent, with several dozen people injured and two men setting themselves on fire. One of them died and the other remains in hospital in critical condition.
Despite his resignation, activists have vowed to continue with the protests.
The Black Sea city of Varna, where the daily rallies against high electricity bills and deepening poverty began two weeks ago, saw its largest demonstration on Sunday, local media reported.
Between 20,000 and 40,000 protesters blocked traffic along key boulevards in the city, calling for the resignation of Kiril Yordanov, the mayor, and denouncing "the economic domination of the mobsters".
They burned an effigy outside the headquarters of the local electricity utility monopoly, Czech Energo-Pro.
About 3,000 protesters also gathered in the Black Sea city of Burgas and between 6,000 and 10,000 joined the demonstration in Bulgaria's second-largest city of Plovdiv in the south, media reports said.
Rallies were also held in numerous other towns across the country.
The protests that have swept the European Union's poorest country over the past two weeks were sparked by anger over mounting electricity bills and frozen public wages.
The average monthly salary in Bulgaria is $534 and has not increased for years.
Activists who met at the weekend said they agreed on the need for constitutional changes with majority elections instead of the current proportional system and the possibility to sue and even sack legislators if they did not fulfill their duties.
They also demanded a moratorium on power bills, no value added tax on electricity and a review of all contracts on privatising the power sector.