The German provocations were partially successful. President Woodrow Wilson ordered the military invasion of Veracruz in 1914 in the context of the Ypiranga Incident and against the advice of the British government. War was prevented thanks to the Niagara Falls peace conference organized by the ABC nations, but the occupation was a decisive factor in Mexican neutrality in World War I. Mexico refused to participate in the embargo against Germany and granted full guarantees to the German companies for keeping their operations open, specifically in Mexico City. These guarantees lasted for 25 years; coincidentally, it was on May 22, 1942, that Mexico declared war on the Axis Powers after the loss of two Mexican-flagged tankers that month to "Kriegsmarine" U-boats.