MOSCOW (Reuters) - President Vladimir Putin has authorised the purchase of Goldman Sachs' unit in Russia by investment company Balchug Capital, a government decree published on Friday showed.

Moscow has steadily tightened restrictions on foreign asset sales since the start of the conflict in Ukraine, with banks requiring Putin's approval for any deal.

A source confirmed Goldman Sachs had entered into a binding agreement to dispose of it Russian subsidiary, subject to various conditions.

Balchug Capital, an Armenian investment fund, did not immediately respond to a request for comment. The fund's CEO and founder David Amaryan oversees all investment activity. Last year, the company acquired U.S. machinery maker Caterpillar's Russian assets.