Flemish nationalists have scored significant gains in weekend municipal elections in Belgium.
Bart De Wever's separatist party called for the northern Flanders region to have greater autonomy from the French-speaking Wallonia region in the south.
He was elected mayor of Antwerp and said he will work for even bigger gains for separatists at the 2014 national elections.
It took Belgium 541 days to form a government after a general election in 2010, mainly because Mr De Wever, leader of the NV-A party, sought extensive concessions for Flemish autonomy.
The Socialist and French-speaking Elio Di Rupo then became Belgian Prime Minister and Mr De Wever went into Opposition.
Mr De Wever now has ended 90 years of Socialist dominance in Antwerp in the municipal elections, and has quickly demanded more rights of self-rule in Flanders.
His eyes are now set on national elections in two years' time.
The 6m Flemish-speakers, in a country of 11m people, will then have to decide whether to support a party that appears intent on dividing Belgium on linguistic lines.
Mr De Wever's victory will not lead to the break-up of Belgium, but it is likely to have an impact on a national level.
He said he sees Belgium disintegrating gradually.
The three Flemish parties in Mr Di Rupo's six-party coalition suffered losses and their efforts to win back voters wanting more powers for Flanders could undermine their cooperation with French-speaking coalition partners.
The federal government is about to begin difficult discussions to settle the budget for 2013.
Mr Di Rupo's coalition is on course to pull the public sector deficit down to 2.8% of gross domestic product this year, from 3.7% in 2011, due to some €13bn of savings and tax increases.
It is estimated it will need to find a further €4-5bn to achieve a deficit of 2.15% in 2013, a target made more difficult with economic stagnation or contraction expected this year and very limited growth next year.