In the midst of the Mexican Revolution, "de facto" President Huerta struggled to defend his power and territory from the forces of Emiliano Zapata in the state of Morelos and the rapid advance of the Northern opposition Constitutionalists under the leadership of Venustiano Carranza. By March 26, 1914, Carranza's forces were from the prosperous coastal oil town of Tampico, Tamaulipas. There was a considerable settlement of U.S. citizens in the area due to the immense investment by U.S. firms in the local oil industry. Several U.S. Navy warships commanded by Rear Admiral Henry T. Mayo were deployed off the coast for the stated purpose of protecting American citizens and property.