Most of the European Union's 27 member countries, including powerhouses France and Germany, go to the polls on Sunday, the final day, with projected overall results due late that evening.
Slovakia's voters have rallied to the ruling left-wing populist Smer-SD party in the wake of the 15 May shooting of Prime Minister Robert Fico, who blamed the attack on the main liberal opposition and its "aggressive and hateful politics".
Authorities said the assassination attempt, by a 71-year-old poet, was politically motivated.
Fico's party opposes EU arms deliveries to Ukraine and rails against alleged "warmongers" in Brussels.
Those are also positions shared with many, but not all, far-right parties in Europe, which are predicted to make gains in the European Parliament.
Surveys suggest they could grab as much as a quarter of the 720 seats, weakening the centrist mainstream groupings which are expected to still come out on top.
TWEET YOUR COMMENT