Japan's economic expansion will probably be sustained and the central bank will adjust interest rates by carefully studying the economy and prices, Bank of Japan Gov. Toshihiko Fukui said Friday at a quarterly meeting of BOJ regional branch managers in Tokyo.

The bank will "continue to contribute to the achievement of sustainable economic growth and price stability," he said, using the same language to describe monetary policy at the previous meeting in April.

Two central bank policymakers said earlier this week that Japan's borrowing costs, the lowest among major economies, need to rise to reflect the economy's strength. Deputy Gov. Toshiro Muto and Policy Board member Kiyohiko Nishimura said keeping rates unchanged for too long could hurt growth in the long run. Economists and investors expect the bank to raise the key rate in August.