4. Spanish Military Against Rif Tribes in Morocco, 1924-1925: Estimated 1,000 Casualties
The Rif Wars were a series of conflicts in Morocco that saw uprisings of the Berber tribes in the mountainous Rif areas against the Spanish colonial government. The Rif Wars occurred from 1921 until 1927.
During this time, the Spanish military became one of the first powers to authorize the use of chemical weapons against a civilian population. Its primary use of chemical weapons was in 1921; between 1924 and 1925, it deliberately targeted civilian populations. An estimated 1,000 people died, but the actual number of casualties may be much higher. The toxic effects of the gas can still be felt today by the people in the Rif region.
