Russian Foreign Minister Sergei Lavrov on Saturday called for "urgent measures" to de-escalate the Ukraine crisis, in a telephone conversation with US Secretary of State John Kerry.
Lavrov "stressed the need for urgent measures to de-escalate the situation in Ukraine, above all to stop military operations against protesters and to put an end to the aggressive activities of the ultra-nationalist Pravy Sektor," or Right Sector movement, Russia's foreign ministry said in a statement.
The nationalist paramilitary group was at the forefront of the pro-European uprising that led to the fall of Ukraine president Viktor Yanukovych.
The two men also discussed "the measures taken to resolve the situation" regarding a group of international OSCE observers who were abducted on Friday in eastern Ukraine by pro-Kremlin rebels during the US-initiated phone call.
In a separate statement, Russia's foreign ministry said Lavrov had held another phone conversation with the OSCE's current chairman, Swiss President Didier Burkhalter.
Burkhalter "thanked the Russians for their efforts to secure the release of the (OSCE) observers", the ministry said.