Ukrainian President Volodymyr Zelensky's demand for an international travel ban on all Russians has triggered heavy criticism in Moscow.
Zelensky's appeal was received "extremely negatively," Kremlin spokesman Dmitry Peskov said on Tuesday, according to the Interfax agency.
"The irrationality of the thought process exceeds every measure," he said.
Zelensky told the Washington Post in an interview published on Monday that "the most important sanctions are to close the borders — because the Russians are taking away someone else’s land."
In the European Union, there are discussions about making the issuing of tourist visas to Russians more difficult, or completely stopping the process altogether.
The Baltic states, for example, only issue visas to Russian citizens in exceptional cases. Finland is also considering tightening its regulations.
In reply to Zelensky's travel sanctions suggestion, Former Russian president Dmitry Medvedev on Tuesday called him "the greatest Ukrainian clown" on Twitter - and even compared him to Nazi dictator Adolf Hitler.
Since the start of Russia's invasion, Medvedev has repeatedly hurled insults at Ukraine, a country he recently suggested may soon not even "exist on the world map."
Moscow frequently justifies its war by saying it is carrying out the the "de-Nazification" of Ukraine, a phrase that causes particular outrage because Zelensky is of Jewish descent.