The European Union (EU) fears today's presidential election in the former soviet state of Belarus will turn to violence.
Observers predict the long-serving president of Belarus, Alexander Lukashenko, will be returned to office in a heavily-rigged vote.
The Opposition has planned peaceful mass rallies to protest.
But the Belarusian security service, the KGB, has warned that the Opposition is planning a violent coup.
Mobile phone companies have reportedly spread that warning through text messages.
EU chiefs say relations with the former soviet state would be damaged if force was used against protesters.
The election campaign itself had already caused concern, as dozens of opposition activists have been arrested and media freedoms cut down.