(CNN) -- Social Democrats leader Jiri Paroubek will step down as party leader after parliamentary elections in the Czech Republic handed his left-of-center party a narrow win -- but not enough seats to govern without forming a coalition.
While the Social Democrats won 22.1 percent of the vote in the weekend election, their major rival -- the center-right Civic Democratic Party -- won 20.2 percent, the election agency said.
The percentages translate to 57 seats for the Social Democrats in the 200-seat lower house of the parliament and 51 seats for the Civic Democratic Party, Czech Television reported.
However, several other smaller and newer parties also captured a number of seats and all of them are right-leaning -- making it likely they may align with the Civic Democrats to form the next government.
Paroubek said Saturday he would resign within 10 days, official broadcaster Radio Prague said.
The party, Paroubek said, will need to examine why the final results were at odds with pre-election opinion polls, which predicted that it would emerge as a clear winner.
In the 2006 elections, Paroubek's party won 32 percent of the votes.
Voters went to the polls on Friday and Saturday to elect a parliament that will replace the caretaker government that has been in charge since last year. They chose from 25 parties.
The government of Prime Minister Mirek Topolanek, of the Civic Democrats, lost a confidence vote in March 2009, forcing him and his Cabinet to resign.
This year, the economic crisis in Europe loomed large in voters' minds.
The right-leaning parties told voters the country could face a fate similar to nearly-bankrupt Greece if it did not curb spending.
The Social Democrats also campaigned for reduced spending, but said they would seek tax hikes for the wealthy to fund social programs.