When the Spanish–American War broke out, American forces sailed for the Philippines and decisively defeated the Spanish Navy.
On that date, Emilio Aguinaldo issued a proclamation ordering, in part, "[t]hat peace and friendly relations with the Americans be broken and that the latter be treated as enemies, within the limits prescribed by the laws of war.
"[20] On 2 June 1899, the Malolos Congress enacted and ratified a Declaration of War on the United States, which was publicly proclaimed on that same day by Pedro Paterno, President of the Assembly.
Emilio Aguinaldo was captured by U.S. forces on 23 March 1901, and swore allegiance to the U.S. on 1 April, appealing to all Filipinos to accept the "sovereignty of the United States ...".
Bands of guerrillas, millenarian movements and other resistance groups continued to roam the countryside, still clashing with American Army or Philippine Constabulary patrols.