In Ukraine, newly elected President Petro Poroshenko has vowed to take action against pro-Russian rebels who shot down a Ukrainian army helicopter near the eastern city of Slovyansk, killing 14 soldiers. The army has been seeking to oust the rebels from eastern areas where they have taken control. The tensions come as representatives from Ukraine, Russia and the European Union meet in Berlin today to address a gas dispute. Russia has threatened to cut off the gas supply to Ukraine if it fails to make a payment by Monday. A third of Europe’s gas comes from Russia; about half that supply passes through Ukraine.