Ukraine leader says 'terrorist' attack on airliner is challenge to whole world

KIEV (Reuters) - Ukrainian President Petro Poroshenko said that the "terrorist" attack on the downed Malaysian airliner over eastern Ukraine on Thursday poses a challenge to the whole world, his website said. "Today's tragedy showed again that terrorism is not localised, but a world problem. And the external aggression against Ukraine is not just our problem, but a threat to European and global security," he said. (Reporting by Natalya Zinets; Writing by Richard Balmforth)