Around 200,000 Spanish troops outnumbered the much smaller rebel army, which relied mostly on guerrilla and sabotage tactics. The Spaniards began a campaign of suppression. General Valeriano Weyler, the military governor of Cuba, herded the rural population into what he called , described by international observers as "fortified towns". These are often considered the prototype for 20th-century concentration camps. Between 200,000 and 400,000 Cuban civilians died from starvation and disease in the Spanish concentration camps, numbers verified by the Red Cross and United States Senator Redfield Proctor, a former Secretary of War. American and European protests against Spanish conduct on the island followed.