The Bank of Japan on Monday left its assessment of Japan's economy unchanged in August but indicated the economy is on a recovery path amid expectations of growth in the United States in the latter half of the year.

"Economic activity remains virtually flat," the central bank said in its monthly report on recent economic and financial developments, repeating a phrase used in July to describe the bank's general view of the world's second-largest economy.

The BOJ said exports and industrial production are expected to remain virtually flat "for the immediate future," suggesting they will start picking up once the growth rate in the U.S. and other overseas economies accelerates in the half-year period beginning July 1.