Prime Minister Pedro Sánchez was the first to receive one of a series of small letter bombs being sent to targets linked to the war effort in Ukraine. The Interior ministry said on Thursday this week that the PM had received a letter with "firework-type" material on 24 November.
On Wednesday this week a worker at the Ukrainian embassy in Madrid was slightly injured when a letter they were opening exploded, prompting a major security alert.
Up to five letter bombs have now been identified. Three more have been sent to: the EU satellite control centre outside Madrid; the Ministry of Defence; and a Zaragoza-based arms manufacturer that provides the grenade launchers Spain is sending to Ukraine.
The letters are being sent by normal post and the one arriving at the embassy appears to have escaped any screening. The letter sent to the PM was intercepted by security officials before it reached his desk and a controlled explosion took place. Sources said the amount of explosive inside the envelopes was small.
The Interior ministry has not ruled out more packages being sent to "companies, people and institutions" in Spain linked to the war against Russia in Ukraine. A Spanish-based person or organisation is being hunted as the letters have been sent from within the country.