Putin told Obama there was a "real threat weighing on the lives and the health of Russian citizens" in Ukraine, according to a Kremlin statement.
The Russian president accused the new government in Kiev of supporting "criminal actions by ultra-nationalists", the Kremlin said.
The two leaders spoke by telephone after Russias parliament authorised military action in Ukraine in a dramatic escalation of tensions.
The Kremlin statement said the conversation was instigated by the US side and focused on the "extraordinary situation in Kiev".
It came after Obamas national security team met Saturday to weigh policy options as Washington tried to keep pace with the fast escalating crisis in Ukraine and Crimea.
(H-RN)
Editor: Ella Syafputri
Copyright © ANTARA 2014
