The center-right party of former Prime Minister Boiko Borisov has fallen far short of winning a majority needed to form a government, according to nearly final election results released on Monday, and appears to have no willing partners to join a coalition.
That would leave the second-place party in position to lead a new government.
Borisov's Citizens for Bulgaria's European Development party amassed the most votes with 30.7 percent, followed by the opposition Socialists with 27 percent with 96 percent of the ballots counted.
Results published by the Central Election Commission showed that two more parties will enter Parliament — the mainly Turkish MRF party with 10.7 percent and the nationalist Ataka party with 7.4 percent.
Borisov led his party to victory in 2009 with just under 40 percent of the vote and headed a minority government, but resigned as prime minister in February amid sometimes violent protests against poverty, high utility bills and corruption.
Six years after Bulgaria's entry into the European Union, the Balkan state of 7.3 million remains the bloc's poorest member.
Many Bulgarians feel squeezed by low wages — the lowest in the EU at 400 euros ($524) a month — and relentless inflation. Cuts in health care and education and other programs in the drive to reduce public debt have also angered many citizens.
Borisov's prospects for forming a coalition government were small as all other parties have refused to join him.
"For the first time in the last 23 years we have a ruling party that has been reelected on top, but strangely enough what has been formed around this party is a 'cordon sanitaire.' Despite winning the election this political party is not in a position to shape the future of the country," political analyst Vladimir Shopov told The Associated Press.
Borisov has not made any statements after the vote.
If he cannot assemble a coalition, the opportunity will go to the Socialists, who said they were ready to seek broad consensus for an anti-crisis cabinet of technocrats to be headed by a former finance minister, Plamen Oresharski.
Socialist leader Sergei Stanishev said his party was ready to meet with all parties except Borisov's, as well as with citizens' organizations for such a cabinet.
"The only option is a programmatic government with strong expert participation and with a clear program," he said.
Analysts are less optimistic, saying that it will be very difficult to form a government that would be able to appease public discontent.
"I expect the country will soon head to another election," said analyst Anton Todorov.
Disappointed with the election results and accusing the politicians with vote rigging, protesters on Sunday shouted "Mafia" and tried to storm the building where party leaders arrived for post-election news conferences. They were stopped by police in riot gear.
Stoyan Petrov, a 49-year-old shopkeeper voiced his frustration with the election outcome. "For so many years now, the same thing is repeating. We will again hear the same old song. I don't see how we can get the country back on a normal track," he said.
Shopov, the political analyst, voiced fears that with some 24 percent of the votes being split among more than 30 parties with none of them reaching the 4 percent hurdle to enter parliament, feelings of being sidelined may fuel anger among their voters.
Voter apathy was widespread, and allegations of vote fraud and a wiretapping scandal marred the campaign.
Weeks ahead of the elections, prosecutors alleged that former Interior Minister Tsvetan Tsvetanov was responsible for illegally eavesdropping on political opponents during his term. He denied it.
However, the scandal deepened as wiretaps leaked in the media revealed that Borisov allegedly had summoned Sofia's chief prosecutor to discuss details of the bribery probe, leading to suspicions of government interference.
On Saturday, prosecutors stormed a printing house and seized 350,000 ballots that were printed beyond the legally fixed number.
Allegations of vote-rigging have accompanied elections in the past, prompting a large team of international observers to monitor the election.
On Monday, the head of the OSCE Election Observation Mission to Bulgaria, Eoghan Murphy, said that "scandals and the recent discovery of additional ballot papers without proper explanation undermined peoples' faith in the political system, and more worryingly, made them question the process itself."
"The electoral process was further negatively affected by pervasive allegations of vote-buying," Murphy told reporters. He also singled out the mistrust between political parties and the current economic difficulties as negative developments.