Russia plans to take legal action over the blocking of gold, forex and assets belonging to Russian residents, Central Bank Governor Elvira Nabiullina said on Monday, adding that such a step would need to be painstakingly thought through and legally justified.

Foreign sanctions have frozen about $300 billion of around $640 billion that Russia had in its gold and forex reserves.

Fifty-two foreign organizations from 12 countries have joined Russia's own financial transfer system, the System for Transfer of Financial Messages (SPFS), developed as an alternative to SWIFT, Nabiullina added.