U.S. says more evidence points to Russia preparing to invade Ukraine
U.S. officials believe Russia is laying the groundwork to invade Ukraine. The National Security Council says Russia has positioned a group of operatives to conduct a so-called "false-flag operation" in eastern Ukraine. Meanwhile, a cyberattack knocked out several government websites in Ukraine on Friday. CBS News correspondent Christina Ruffini has the latest, and UCLA political science professor Daniel Treisman talks to CBSN's Lana Zak about why these moves are significant.