The Swedish general election has left the two main political blocs almost tied, with the anti-immigration party making gains on its previous results, reports BBC.
With nearly all ballots counted, the governing centre-left coalition is marginally ahead of its centre-right Alliance rivals, with around 40% each.
The nationalist Sweden Democrats (SD) have won about 18% of the vote, up from 12.9% in the previous election.
A protracted battle to form a working coalition now looks a certainty.
Sweden uses a system of proportional representation, under which each party is allocated a number of seats in each constituency that is broadly in line with its share of the vote.
Both of the main blocs have refused to govern with the SD, although its leader said he was prepared to talk with all other parties.
"We will increase our seats in parliament and we will gain huge influence over what happens in Sweden during the coming weeks, months and years," Jimmie Akesson told a party rally.
Other European countries have seen support rise for anti-immigration parties in recent years. Earlier this year, Italy installed a new coalition government run by the anti-establishment Five Star and the right-wing League. In 2017 the far-right Alternative for Germany won 12.6% of votes, and The Danish People's Party won 21% in 2015.
Sweden's ruling coalition, headed by outgoing PM Stefan Lofven, is made up of his Social Democrats and the Green Party, and is supported in parliament by the Left Party.
The centre-right Alliance is made up of four parties. Its candidate for PM is Ulf Kristersson, head of the Moderates. He said the ruling coalition had run its course and should resign.
But Lofven said he would not quit. He told a party rally: "We have two weeks left until parliament opens. I will work on calmly, as prime minister, respecting voters and the Swedish electoral system."
Both the Social Democrats and the Moderates saw their percentage of the vote fall, as the SD and smaller parties picked up votes. However, even the SD performance was down on what some opinion polls had suggested.
Analysts suggest it may be easy for the centre-right bloc to form a working coalition, although it will take complicated negotiations.
Immigration has been a central issue of the campaign. The SD is seeking strong curbs on immigration. Lofven has described it as "racist".