By Oana Lungescu
BBC News, Brussels
The alliance of socialists in the EU has expelled Slovakia's ruling Social Democratic Party (Smer) for forming a coalition with a far-right party.
Robert Fico is politically out in the cold
It is the first time that the European socialist bloc, which includes 33 parties from across 28 European countries, has taken such a step.
Although largely symbolic, it is an embarrassing political blow to the Slovak Prime Minister, Robert Fico.
It is also being seen as a warning to others in Europe.
The Slovak Social Democrats keep their seats in the European Parliament, but politically they are out in the cold.
Mr Fico, who came to power in last June's election, will no longer be invited to the gatherings of European leaders that the Party of European Socialists usually hold before EU summits.
Alarmed by violence
The suspension will be reviewed next June, but the president of the European socialists warned that member parties could not enter government at any price, by compromising with extreme nationalism and xenophobia.
EU leaders have been alarmed at the rise in violent incidents against Slovakia's half-a-million ethnic Hungarians, after Mr Fico brought the Slovak National Party into the ruling coalition.
Its leader, Jan Slota, once urged a crowd of supporters to get into their tanks and flatten the Hungarian capital Budapest.
He has also made derogatory remarks about Slovakia's sizeable community of Roma (Gypsies).
The decision to suspend the Slovak Social Democrats was taken by an overwhelming majority, reflecting concerns about the rise of the far-right, not only in the former communist bloc, but also in Western European countries like France and Belgium.