Moderate party secretary, Gunnar Strommer, said after the exit polls were published that he thinks "it's pretty clear" Lofven will need to resign. "And the Social Democrats and a Social Democratic-led government is a guarantee for not letting the Sweden Democrats extremist party, racist party, get any influence".
With almost all ballots counted, the governing centre-left coalition is marginally ahead of its centre-right Alliance rivals, with around 40 percent each.
"We're now competing against the Social Democrats and Moderates to become the biggest party in the country", he said, dismissing the protesters as "communists". However, the results were closer to one in six.
That message has resonated with a growing number of people in recent years, as concerns rose over high-profile incidents of gang violence, an influx of refugees and regional economic inequality.
"This government has run its course..."
The poll projects that the ruling party received 26.2 percent of the vote.
That could weaken the Swedish crown in the short term, but analysts do not see any long-term effect on markets from the election because economic growth is strong, government coffers are well stocked and there is broad agreement about the thrust of economic policy.
The "Red Green" combination of the Social Democrats, the Greens and the Left won 40.6 per cent of the vote and (on preliminary figures) 144 seats.
The trouble is, the two centre-most parties of the centre-right bloc (the Centre and Liberal party) have said that they will not under any circumstances consider that.
Mr Akesson challenged Ulf Kristersson, the centre-right Alliance's candidate for the premiership, to choose between seeking support from the Sweden Democrats and the incumbent Social Democrat prime minister Stefan Lofven.
The Alliance would need the far-right's support to obtain a majority in parliament.
Swedish right and left neck-and-neck as anti-immigration party gains
Results were based on 99% of the vote confirmed and will not be finalized until Wednesday when overseas votes are counted. Meanwhile, next-door in Finland, the populist True Finns party was included in the center-right government in 2016. One option could be for one of the parties to switch alliances. "They're more direct", Elias, an 18-year-old voting in his first election, told AFP.
Parliament opens on September 25.
When the Social Democrats finally did address public concerns over immigration and crime during the campaign earlier this year, the party mimicked numerous talking points and policies of the far-right.
The opposition Moderate party is also unable to take over because even an established alliance with the centre-right parties doesn't make up the numbers needed for a majority. And when the pivotal and most dynamic grouping is a blatantly anti-immigrant party, it is time to be rattled.
The latest opinion poll suggests that Prime Minister Stefan Lofven's ruling Social Democrats will substantially lose seats but still emerge a victor with an estimated 24.9 percent of the votes.
An anti-immigration party has won nearly 20% of votes in the Swedish election, an early exit poll suggests. "Everything is about us", Akesson said.
Voters in Sweden appear to be split in an unpredictable general election that may turn into one of the most thrilling races in the Scandinavian country's history for decades amid heated debate on immigration.
The move has polarised voters and fractured the long-standing political consensus. Voters on Sunday did not doubt the Nordic welfare model, but many hesitate to let more immigrants without similar cultural traits share the system.
The SD wants to freeze immigration, leave the European Union, crack down on crime and are climate change sceptics. However, the centrist parties all oppose such a vote, so it is unlikely to go ahead.
Since 2015, the center-left government has sharply restricted immigration, but many Swedes complain that society can not cope with integrating so many newcomers, many of them Muslims from Africa and the Middle East.
During the heatwave, around 25,000 hectares of forest burned in wildfires.