SOFIA (AFP) - Bulgaria's government quit on Wednesday, Prime Minister Boyko Borisov announced, after days of sometimes violent protests sparked by sharply higher electricity prices expanded into nationwide demonstrations.

The surprise announcement paves the way for elections that had been scheduled for July in the European Union's poorest member to be brought forward.

"It is the people who put us in power and we give it back to them today," Mr Borisov told parliament.

He said he would not be part of any interim government.

"I will not participate in a government where the police beat up people or where threats for protests replace political dialogue. If the street wants to govern the country, let it do it," the 53-year-old said.

Mr Borisov, a right-wing ex-bodyguard, had on Tuesday ruled out resigning.

Bulgaria has been shaken over the past 10 days by protests that were first focused on soaring electricity prices but then grew into nationwide demonstrations against the right-wing government in general.

Clashes left dozens of people wounded and scores were arrested as demonstrators fought running battles with riot police and vandalised government buildings, police cars and shops in the capital Sofia.

In the latest disturbances late on Tuesday, 15 demonstrators and two policemen were injured and 25 people were arrested in Sofia. The previous evening 11 people, including five police officers, were hurt.

A 36-year-old man doused himself with petrol and set himself on fire early Wednesday outside city hall in Varna in the east where the first protests erupted, media reports said. He was hospitalised with 80-per cent burns.

Another man, who was mentally ill, died after setting himself alight in the central city of Veliko Tarnovo on Monday.

Mr Borisov attempted to take the heat out of the crisis by announcing on Monday the sacking of the unpopular finance minister and on Tuesday saying he would revoke the licence of Czech electricity firm CEZ.

Non-eurozone Bulgaria's economy struggled to grow in 2012, expanding by just 0.1 per cent in each of the past two quarters because of the global slowdown and as foreign investment has slumped.

Official unemployment hit 11.4 per cent in December but trade unions say the real figure is closer to 17 or 18 per cent of the workforce. Inflation meanwhile hit 4.4 per cent last month.

Voters are also angry at what they see as Mr Borisov's failure to stamp out corruption and cronyism despite repeated calls by the EU to clamp down on graft since joining the bloc in 2007.

His government's resignation was due to be formally tabled at noon (1000 GMT) to parliament, which will have to call early elections. A caretaker cabinet will govern in the meantime.

Analysts have long said that the once hugely popular Borisov - a former firefighter, bodyguard and police chief - was losing his sway with voters as the end of his government's term neared.

Support for his right-wing GERB party has eroded to about 22 per cent, about the same as for the opposition Socialists, a recent Gallup poll showed.

Mr Borisov's personal approval rating was also down to an unprecedented 29 per cent, or as much as that of Socialist leader Sergey Stanishev.

Even if Mr Borisov's resignation was what the street rallies pressed for, analysts were divided on Wednesday over whether it would ease public anger.

"This move of Borisov aims to put out the fire of the protests. But we are yet to see if it will work," political analyst Rumyana Kolarova told state BNT radio.

For Gallup analyst Kancho Stoychev, however, "the resignation was the only right move in the current situation".