The Spanish–American War was a ten-week conflict that occurred in the spring and summer of 1898. Cuba had been waging a war of independence against Spain since 1895, an effort largely supported by the United States (which had extensive economic interests on the island). To ensure the safety of American citizens and property in Cuba, the United States sent the battleship to Havana in late January 1898. The "Maine" exploded under mysterious circumstances and was destroyed with large loss of life on February 15. American newspapers whipped up war fever, and held Spain responsible for the ship's destruction. The United States Congress enacted a joint resolution demanding independence for Cuba, and President William McKinley signed it into law on April 20. In response, Spain severed diplomatic relations on April 21. The same day, the United States Navy began a blockade of Cuba. Spain declared war on April 23. On April 25, Congress declared that a state of war between the U.S. and Spain had existed since April 21.