KYIV (Reuters) - Ukrainian Foreign Minister Dmytro Kuleba said on Thursday he had spoken to the Organization for Security and Cooperation in Europe (OSCE) about Russia’s “systemic aggravation” of the security situation in eastern Ukraine and Crimea. Kyiv and Moscow have traded blame in recent weeks for a spike in violence in the eastern Donbass region, where Ukrainian troops and Russian-backed forces have fought a conflict that has killed 14,000 people since 2014 by Ukraine’s estimate.