Reflecting continued concern about the fragility of the country's economic recovery, the Bank of Japan announced Friday it was maintaining its low interest rate monetary policy.

"The Bank of Japan will encourage the unsecured overnight call rate to remain at effectively zero percent," the central bank said in a statement, referring to its operations in the call market, where financial institutions borrow and lend to each other.

The decision taken at its most recent policy meeting comes amid rising market expectations that the BOJ may begin raising rates by summer, when it is expected to reduce the outstanding balance of current account deposits held by at the central bank to the legally required level of about 6 trillion yen.