A spokesperson for Russian President Vladimir Putin told reporters on Tuesday that the outcome of his country's talks with the U.S. in Riyadh "has been reported in the capitals" and is currently being "analyzed" by Moscow and Washington.

Russia and the U.S. met there a day earlier on a limited Black Sea ceasefire proposal that Washington hopes will open the way for broader peace negotiations.

Karasin, 75, is a career diplomat whose past roles include deputy foreign minister and ambassador to Britain. He is now a member of the Federation Council, the upper house of Russia's parliament, and chairs its international affairs committee. Both he and Beseda have been placed under Western sanctions.