Even historically neutral Switzerland is adopting the EU's sanctions against Russia, President Ignazio Cassis announced Monday. The country, which is a major center for wealthy Russian oligarchs, said it's freezing the assets of certain individuals "with immediate effect."

Among the high-profile names were close Putin allies Igor Sechin, head of state oil giant Rosneft, and Nikolay Tokarev, boss of pipeline mammoth Transneft.

Three men ranked within Russia's 10 top richest by Forbes were also added: metals magnate Alexei Mordashov, tycoon Alisher Usmanov, and businessman and Putin friend Gennady Timchenko.