As part of the offensive the Aviazione Legionaria and the Legion Condor bombed Durango, a town of 10,000 inhabitants that was also a key road and railway junction behind the frontline.

Mola said that: "I have decided to terminate rapidly the war in the north: those not guilty of assassinations and who surrender their arms will have their lives and property spared.

While the local road junction meant that Durango was a legitimate target for an air attack and the bombing did not contravene the laws of war as they were at the time, foreign observers were shocked at the carnage.

Queipo de llano said that: "our planes bombed military objectives in Durango, and later communists and socialists locked up the priests and nuns, shooting without pity and burning the churches".

Instead, it was the bombing of Guernica, a similar air attack that took place four weeks later, that came to symbolize the horrors of modern aerial warfare in the public consciousness.