Exit polls had initially predicted a narrow victory for left-wing Andersson's camp but as the evening wore on, and the vote count supplanted the exit poll, the results tipped in favor of the conservatives.
Near final results in Sweden's election on Sunday show that a bloc of right-wing parties was expected to defeat a left-wing bloc headed by Prime Minister Magdalena Andersson.
The conservative group includes a populist anti-immigration party that made its best ever showing.
However, the result was so close that the election authority said it would not be known before Wednesday when some uncounted votes, including those cast abroad, have been tallied.
According to the early count, Andersson's ruling left-wing Social Democrats won 30.5 percent of the vote, more than any other party. However, a bloc of four left-wing parties appeared to fall short as a whole of winning a majority of votes in the 349-seat parliament, or Riksdag.
Exit polls had initially predicted a narrow victory for Andersson's camp but as the evening wore on, and the vote count supplanted the exit poll, the results tipped in favor of the conservatives.
Early Monday, the conservatives appeared to have 176 seats to 173 for the center-left.
READ MORE: Sweden votes in election marked by crime, energy crisis
'Shift in power'
In a speech to her supporters, Andersson said that while the results were unclear, it was obvious that the social democratic movement, which is based on ideals of creating an equal society and a strong welfare state, remains strong in Sweden.
The biggest winner of the evening was the populist anti-immigration party, the Sweden Democrats, which had a strong showing of nearly 21 percent, its best result ever. The party gained on promises to crack down on shootings and other gang violence that have shaken a sense of security for many in Sweden.
The party has its roots in the white nationalist movement but years ago began expelling extremists. Despite its rebranding, voters long viewed it as unacceptable and other parties shunned it. But that has been changing, and its result in this election shows just how far it has come in gaining acceptance.
“We are now the second biggest party in Sweden and it looks it’s going to stay that way," party leader Jimmie Akesson told his supporters.
“We know now that if there’s going to be a shift in power, we will be having a central role in that," he said. "Our ambition is to be in the government.”
The conservative bloc was led during the campaign by the center-right Moderates, which won 19 percent. It was previously the country's second largest party.
Moderates leader Ulf Kristersson told his supports that he stands ready to try to create a stable and effective government.
Regardless of the election outcome, Sweden is likely to face a lengthy process to form a government, as it did after the 2018 election.
Andersson, a 55-year-old economist, became Sweden’s first female prime minister less than a year ago and led Sweden’s historic bid to join NATO following Russia’s incursion on Ukraine in February.
READ MORE: Exit polls: Slender lead for Sweden's ruling left bloc amid far-right surge