Spanish police said six letter bombs sent to high-profile targets in recent days appeared to have been posted from the northern city of Valladolid, a source close to the investigation told Reuters on Saturday.
The devices were sent to targets including Prime Minister Pedro Sanchez, the Ukrainian Embassy in Madrid, government offices, a European Union satellite company and the US Embassy between Nov. 24 and Dec. 2.
Most were defused, although an employee at the Ukrainian embassy was slightly injured when one of the devices ignited.
No person has been identified as the sender of the packets, said the source, who asked not to be named in order to discuss the investigation.