Bulgarians upset over record-high energy prices took to the streets this week, demanding the nationalization of three foreign-owned power companies.

The protests, which began Sunday in 15 cities and towns, continued Monday around the country. In Sofia, Bulgarian Minister of Economy, Energy and Tourism Delian Dobrev was pelted with snow while attempting to meet with demonstrators, the Sofia News Agency reported.

Energy bills for Bulgarian consumers went up nearly 14 percent in July and residents were especially hard-hit in December, triggering a simmering anger aimed at the Czech Republic utilities CEZ and Energo-Pro and EVN Group of Austria that erupted over the weekend.

EVN said Monday to two of its company cars had been torched while demonstrators were arrested after clashes with police in at least two Bulgarian cities, authorities said.

Protests continued Monday in Varna, Plovdiv and Blagoevgrad, where demonstrators chanted, demanded rebates, adjustments and penalties against the companies for record-high bills, BTV television reported.

Around 1,500 protesters in Varna stopped traffic while denouncing the power companies as "mafia." After being stopped by riot police while marching to the city's cathedral, they headed toward the city hall but were prevented from a cordon of riot police from crossing a bridge.

In Blagoevgrad protesters vowed not to pay their bills and called for the government to nationalize the companies, the broadcaster reported.

Dobrev on Sunday said he and Deputy Prime Minister and Finance Minister Simeon Dyankov had worked out a deal with CEZ, EVN and Energo Pro to allow for deferred payment of consumer energy bills.

He blamed the high prices on a longer billing period in December, which included 10 more days than a normal month, as well as more holiday days this year and lower average temperatures.

Lower standard voltages in some parts of the country also have played a role in the price spikes, he said, adding the companies have agreed to make investments to standardize the voltage across the country.

Bulgarian President Rosen Plevneliev said Monday after meeting with center-right governing coalition partners that nationalizing the energy companies isn't the answer and wouldn't result in lower electricity prices, BTV reported.

"Power bills will not fall through nationalization," he said. "They can only fall through market liberalization and investments in energy efficiency."

He renewed calls for the breakup and privatization of the government-owned Bulgarian Energy Holding, which controls the National Electric Company NEK and the gas monopoly Bulgargaz.

The opposition Bulgarian Socialist Party, meanwhile, agreed with the demonstrators' criticism that the government, led by the center-right GERB party, is siding with power company "monopolies" over the interests of consumers.

"When there is no state to protect the people, it leads precisely to such extreme protests because people have been brought to the brink," BSP leader Sergey Stanishev said.

"Any monopoly imposes its interests and here we feel very clearly the lack of serious government. What does the government do? Everywhere you turn there is a monopoly that is not effectively regulated by the state."