As well as electing their representatives to the next European parliament, Belgians were also being called to vote in crucial regional elections.
As predicted, initial results show Prime Minister Herman Van Rompuy’s Christian Democrats coming out on top in Flanders.
However, in the French-speaking Brussels and Wallonia regions, early indications show the Socialists and the Liberals are neck and neck.
The results have prompted socialist leader Elio di Rupo to say that maybe the Socialist Party would remain number one in Wallonia, although he added it was best to wait for final results.
The race could also bring victory to his main rival, Liberal movement leader Didier Reynders in the Brussels region.
Analysts believe the nationwide changes of power could deprive prime minister Rompuy of his majority in parliament.
This could lead to early elections, and prompt Flanders to reiterate its calls for greater autonomy – further threatening Belgian unity.