Ukraine obtains classified data on Russia's newest nuclear submarine, intelligence claims * 'Productive' phone call with Trump focused on ending war, sanctions, drone production, Zelensky says * Three Nordic countries to fund $500 million in US weapons for Ukraine * Russia considers air truce proposal to Trump without ending war,

WASHINGTON, Aug 1 (Reuters) - U.S. President Donald Trump on Friday said he had ordered two nuclear submarines to be positioned in "the appropriate regions" in response to remarks from former Russian President Dmitry Medvedev about the risk of war between the nuclear-armed adversaries.