The Mexican Revolution involved a civil war with hundreds of thousands of deaths and large numbers fleeing combat zones. Tens of thousands fled to the U.S. President Wilson sent U.S. forces to occupy the Mexican city of Veracruz for six months in 1914. It was designed to show the U.S. was keenly interested in the civil war and would not tolerate attacks on Americans, especially the 9 April 1914, "Tampico Affair", which involved the arrest of American sailors by soldiers of the regime of Mexican President Victoriano Huerta. In early 1916, the Mexican general Pancho Villa ordered 500 soldiers on a murderous raid on the American city of Columbus New Mexico, with the goal of robbing banks to fund his army.