Operación Ogro (Operation Ogre) was the name given by the Basque liberation group ETA (Euskadi Ta Askatasuna) to its assassination of Admiral Luis Carrero Blanco, the Prime Minister of Spain, on 20 December 1973. 

Over five months an ETA commando unit using the code name Txikia dug a tunnel under the street from their rented basement flat in Madrid – telling the landlord that they were student sculptors to hide their true purpose. The tunnel was packed with 80 kg of explosives that had been stolen from a Government depot.

On 20 December, a three-man ETA commando unit disguised as electricians detonated the explosives by wire as Blanco’s car passed. The blast sent Blanco and his car 20 metres into the air and over a five-storey building. The car crashed to the ground on the opposite side of a Jesuit college, landing on the second-floor balcony.