VLADIVOSTOK, Russia, Dec. 29 (UPI) -- A day after his country tested a long-range missile, Russian Prime Minister Vladimir Putin said he is seeking information on U.S. defense plans. Putin, speaking Tuesday in Vladivostok in eastern Russia, said U.S. plans for defensive shields forces Moscow to develop additional offensive weapons to keep a "balance." He said if the United States had a strategic edge it may become more "aggressive." The United States and Russia are in negotiations to find a successor for the Strategic Arms Reduction Treaty of 1991. That agreement expired Dec. 5.