Two exit polls gave Sweden's left-wing bloc led by Social Democratic Prime Minister Magdalena Andersson a slim lead in Sunday's general election, and also indicated a far-right surge.
The four left-wing parties were credited with 50.6 percent of voter support in an exit poll published on TV4 compared to 48 percent for the four parties on the right.
A second exit poll on public broadcaster SVT gave the left 49.8 percent and the right 49.2 percent.
Both polls, published after voting closed Sunday, also suggested that the anti-immigration and nationalist Sweden Democrats could for the first time become the country's second-biggest party. They credited the party with 21.3 and 20.5 percent of votes respectively.
The election campaign has been dominated by rising gang shootings, immigration and integration issues, and soaring electricity prices.
If the exit polls are confirmed, the far-right surge would mean they overtook the traditional leaders of the right-wing bloc, the conservative Moderates, whose party leader Ulf Kristersson is challenging Andersson for the post of prime minister.
That would be a heavy blow to Kristersson, who orchestrated a major shift in Swedish politics by initiating exploratory talks in 2019 with the Sweden Democrats, long treated as "pariahs" by other political parties.
The two other small right-wing parties, the Christian Democrats and to a lesser extent the Liberals, later followed suit.
- Tough days ahead -
If the final results were to confirm the left bloc's lead, Prime Minister Andersson, a 55-year-old former finance minister, would try to build a government with the support of the small Left, Centre and Green parties.
The Social Democrats have governed Sweden since 2014.
Voter turnout was expected to be high, with more than 80 percent of the country's 7.8 million eligible voters expected to cast ballots.
Andersson, whose party has dominated Swedish politics since the 1930s, enjoys broad support among Swedes.
She consistently led Moderates leader Ulf Kristersson, her challenger for the post of prime minister, by a wide margin in opinion polls.
Yet pollsters also put the two blocs in an almost dead heat.
Both blocs are beset by internal divisions that could lead to lengthy negotiations to build a coalition government.
But for a number of reasons there is "pressure to have a united and effective government" in place quickly, said political scientist Katarina Barrling.
Sweden faces a looming economic crisis, is in the midst of a historic NATO application process and is due to take over the EU presidency in 2023.
- 'Enormous shift' -
The end of the Sweden Democrats' political isolation, and the prospect of it becoming the biggest right-wing party, is "an enormous shift in Swedish society", said Anders Lindberg, an editorialist at left-wing tabloid Aftonbladet.
Born out of a neo-Nazi movement at the end of the 1980s, the Sweden Democrats entered parliament in 2010 with 5.7 percent of votes. They won 17.5 percent in 2018.
The party's surge comes as Sweden struggles to combat escalating gang shootings attributed to battles over the sales of drugs and weapons.
The country now tops European statistics for firearm deaths.
While the violence was once contained to locations frequented by criminals, it has spread to public spaces such as parks and shopping centres, sparking concern among ordinary Swedes in a country long known as safe and peaceful.