According to a police source, the post office in Amsterdam was receiving threatening messages before the incident.
“Today morning, an explosion occurred in the mailroom of a commercial building in Bolstoen. It is assumed that the explosion was caused by a bomb placed in a letter. No injuries yet”, the police wrote on Twitter after the first blast.
Police later reported that another explosion occurred in the southern Dutch city of Kerkrade.
The news comes after five Dutch companies, based in Amsterdam, Rotterdam and Utrecht, received letter bombs last month. However, none of them exploded.
Following the incidents, police reportedly warned citizens to be alert for any letters from CIB in Rotterdam.