Letters containing powder have been sent to the offices of a number of ministers in Belgium’s caretaker federal government. The offices of the Prime Minister Sophie Wilmès and the Deputy Prime Minister Alexander Decroo were among those targeted. The police, fire service and a decontamination team attended the scene. An investigation has been launched into the nature of the powder and who sent the letters. On Thursday a number of Walloon regional ministers were sent letters containing powder. These turned out to be harmless.