Shortly after the USA defeated Spain and annexed the Philippines, Filipino revolutionaries fought to gain independence. Casualties were estimated at 34,000–1,000,000.
While both sides undoubtably committed some atrocities, American troops burned entire villages to the ground, placed many civilians in concentration camps and employed torture (notably, water boarding).
Many Americans, including Mark Twain and William Jennings Bryan, opposed the annexation of the Philippines as colonialism.
“Our Boys entrenched against the Filipinos.” NARA; Ca. 1899-1900 ; Public Domain