Russia sees no reason for United Nations peacekeepers to be sent to Ukraine, RIA news agency quoted the Russian foreign ministry as saying.
A new round of talks between Russia and Ukraine will be held via video link.
Earlier presidential adviser Oleksiy Arestovych in a televised interview on Monday said more than 2,500 residents of the Black Sea port city of Mariupol have been killed since Russian invaded Ukraine on Feb. 24.
He said he was citing figures from the Mariupol city administration, and accused Russian forces of preventing humanitarian aid reaching the encircled city on Sunday.
Russia says it does not target civilians.