"At present, there is no possibility for me to form a government," she told a press conference on Monday morning.
At 11am, parliament convenes to elect a new speaker. The Left Party has announced that it intends to vote for incumbent speaker Andreas Norlén, of the Moderate Party, rather than a candidate from the centre-left bloc.
ANALYSIS: From the obvious to the unthinkable – nine options for Sweden's government
More to come