Total reserve assets slipped 8.3 percent, compared to $107.3 billion at the end of May, according to the bank's international reserves and foreign currency liquidity report. 

Last month, foreign currency reserves -- in convertible foreign currencies -- amounted to $74 billion, down 8.9 percent on a monthly basis. 

CBRT's gold reserves -- including gold deposits and, if appropriate, gold swapped -- also dropped by 6.8 percent to $22.8 billion in June compared to May. 

On a yearly basis, the bank's official reserves saw a decline of 9 percent, versus $108.7 billion at the end of June 2017.

In mid-December 2013, the bank's total reserves hit their all-time peak at nearly $136 billion, including some $21 billion in gold reserves.