Ukraine troops in Donbass (Photo: Reuters)

Earlier in the day, Russian presidential spokesman Dmitry Peskov announced that Deputy Foreign Minister Sergey Ryabkov is ready to fly to any neutral country for talks.

Foreign Affairs Department spokeswoman Lea Zurcher said Switzerland is ready to offer its services if they are desired, including organizing or coordinating discussions and meetings.

Tensions over Ukraine have been rising in recent weeks. Russia has repeatedly denied accusations of aggression, pointing to NATO's military activity near Russia's borders, which it deems a threat to its national security. Russia said it defended its right to move military forces freely within its own territory.