(Reuters) - Global index provider MSCI Inc said on Monday it was closely monitoring developments in Ukraine and access to the Russian equity market in the face of possible investment sanctions amid rising concerns about a potential Russian invasion.

       Russia has more than 100,000 troops massed near the border of Ukraine. It denies Western accusations that it is planning an invasion, but says it could take unspecified "military-technical" action unless a range of demands are met, including barring Kyiv from ever joining the NATO alliance.

       The United States is relocating its Ukraine embassy operations from the capital Kyiv to the western city of Lviv, Secretary of State Antony Blinken said on Monday, citing a "dramatic acceleration in the buildup of Russian forces".

       Western countries have threatened sanctions on an unprecedented scale if Russia does invade. The Group of Seven large economies (G7) warned of "economic and financial sanctions which will have massive and immediate consequences on the Russian economy".

       (Reporting by Dania Nadeem in Bengaluru; Editing by Shounak Dasgupta)