People vote at a polling station during the Swedish general elections in Stockholm on Sunday. A left-leaning coalition led by Sweden's opposition Social Democrats defeated the incumbent center-right government in Sunday's election, while the far right made historic gains. Photo: AFP

Sweden's outgoing Prime Minister Fredrik Reinfeldt waves after addressing an election night party of the Moderate Party in Stockholm on Sunday. Reinfeldt, who has presided over a four-party center-right coalition for the past eight years, conceded defeat in the country's general election and said he would hand in his resignation on Monday. Photo: AFP

Social Democratic Party supporters celebrate following general election results in Stockholm on Sunday. The winner of Sweden's election, Social Democrat leader Stefan Lofven, 57, embarked Monday on the difficult task of forming a government while keeping his pledge to exclude the hugely strengthened far-right party. Lofven was expected to explore the possibility of a coalition involving the Greens and perhaps the former communist Left Party. The Social Democrat-led, left-green group got a total of 43.6 percent of the vote. Photo: AFP

Opposition leader Asa Romson (left) of the Green Party shakes hands with Stefan Lofven of the Social Democrats on Sunday at the Swedish national television channel SVT in Stockholm, after the prime minister's resignation following the Swedish general elections. The real upheaval on Sunday was a massive gain for the far-right Sweden Democrats, which only entered parliament in 2010 and have now more than doubled their support to 13 percent, to become the third-largest party. Photo: AFP