High electricity bills brought hundreds of people onto the streets of several Bulgarian cities to protest on Sunday.
In the capital Sofia banners read “mafia”, “resign”, and “no to legalised racketeering”.
Prices went up by 13 per cent last July but it has taken the cold winter for the impact to be felt.
There is anger at the influence of foreign companies. Bulgaria’s power distribution market is divided into three regions, controlled by Czech firms CEZ and Energo-Pro, and Austria’s EVN.
“We want all these electricity distributors to disappear from Bulgaria. They continue milking us, ordinary people, with the support of the state,” said protester Yanko Petrov.
Two EVN cars were burnt overnight, the company said, condemning the attack.
The Energy Minister Delyan Dobrev explained that some bills were higher because they covered a longer period than usual, to take in the Christmas holidays.
But when he came out of the ministry to try to talk to demonstrators, he was hit by a snowball from the crowd.
The ministry has ordered checks on the higher bills, while power distributors also say they are investigating complaints.
Electricity prices are politically sensitive in Bulgaria since power bills eat into a large part of people’s incomes, where pay averages 350 euros a month.