VANDENBERG AIR FORCE BASE, Calif., Jumada I 17, 1437, Feb 26, 2016, SPA -- The U.S. military test fired its second intercontinental ballistic missile in a week late on Thursday to demonstrate the reliability of American nuclear arms at a time of rising strategic tensions with countries like Russia and North Korea, Reuters reported. The unarmed Minuteman III missile blasted off from a silo at Vandenberg Air Force Base in California shortly before midnight, a Reuters reporter witnessed, headed toward a target area near Kwajalein Atoll in the Marshall Islands of the South Pacific. Deputy Defense Secretary Robert Work said the U.S. tests, conducted at least 15 times since January 2011, send a message to strategic competitors like Russia, China and North Korea that Washington has an effective nuclear arsenal. "That's exactly why we do this," Work told reporters prior to the launch. "We and the Russians and the Chinese routinely do test shots to prove that the operational missiles that we have are reliable. And that is a signal ... that we are prepared to use nuclear weapons in defense of our country if necessary." --SPA 10:59 LOCAL TIME 07:59 GMT www.spa.gov.sa/w