QUITO: Letter bombs were sent to at least five journalists working in TV and radio stations in violence-plagued Ecuador Monday, one of which exploded without causing serious injury, Interior Minister Juan Zapata said.

The prosecutor’s office said it had opened an investigation into the crime of terrorism, without stating why the news stations were specifically targeted, or by whom.

The interior minister said the envelopes were sent from the town of Quimsaloma, in the coastal province of Los Rios.