On March 25, the bank had said it would buy gold at a fixed price of 5,000 roubles a gram until June 30.

Since that announcement, the rouble has strengthened sharply against the dollar. Five thousand roubles was worth around $52 on March 25 and around $63 on Thursday.

Gold prices on the international market have remained stable at around $60 a gram, or $1,900 an ounce.

Russia is one of the world's biggest gold producers, but the country's refiners were barred from selling bullion into the London market, the world's largest, after the Kremlin sent troops into Ukraine in February.

($1 = 78.6830 roubles)

(Reporting by Reuters; writing by Peter Hobson, Editing by Mark Trevelyan)