Ballots at a polling station in Tomelilla, Sweden September 9, 2018. TT News Agency/Johan Nilsson via REUTERS

STOCKHOLM (Reuters) - Sweden’s center-left parties held a slim lead over the rival center-right Alliance in the Nordic country’s general elections, a voter poll by national broadcaster TV4 showed on Sunday.

The Sweden Democrats, anti-immigration nationalists that have been shunned by all other parties, recorded gains, as expected, depriving both the left- and right-wing blocs of a majority.

The ruling center-left Social Democrats and Greens and their Left Party allies in parliament got 41.0 percent of the vote and the Alliance 40.1 percent. The Sweden Democrats rose to 16.3 percent from 12.9 percent in the previous election, the poll showed.

A traditional exit poll by the SVT public broadcaster, due out when voting finishes at 1800 GMT, is bigger and, historically, it has been more accurate in predicting the actual election result.