The Moros on Mindanao and on the Sulu Archipelago, suspicious of both Christian Filipino insurrectionists and Americans, remained for the most part neutral. In August 1899, an agreement had been signed between General John C. Bates, representing the United States government, and the sultan of Sulu, Jamal-ul Kiram II, pledging a policy of noninterference on the part of the United States. In 1903, however, a Moro province was established by the American authorities, and a more forward policy was implemented: slavery was outlawed, schools that taught a non-Muslim curriculum were established, and local governments that challenged the authority of traditional community leaders were organized. A new legal system replaced the sharia, or Islamic law. United States rule, even more than that of the Spanish, was seen as a challenge to Islam. Armed resistance grew, and the Moro province remained under United States military rule until 1914, by which time the major Muslim groups had been subjugated.
...The Spanish, who ruled the islands until 1898, when they were driven out by Americans, let them [the Moros] follow their age-old way of life and did not try to convert them, but the Americans felt differently. They wanted them to become assimilated, but the Moros resisted with sporadic outbreakes beginning in 1901. In 1903, they attacked American troops stationed near Lake Lanos in the interior of Mindanao. On the nearby island of Jolo in 1906, some 600 rebellious Moros who had taken refuge inside the crater of a large volcano (Mt. Dajo) were slaughtered by US troops under General Leonard Wood (1860-1927). This raised a cry of indignation from the public. Fighting ceased after June 1913, and the Moros continued to practice their religion and traditions in peace.