The U.S. Treasury Department added Japan to its "monitoring list” for foreign-exchange practices but stopped short of labeling it or any other trade partner as a currency manipulator.

While pointing out that Japan intervened to support the yen earlier this year, the Treasury took aim, instead, at Tokyo’s large bilateral trade and current account surpluses.

"Treasury’s expectation is that in large, freely traded exchange markets, intervention should be reserved only for very exceptional circumstances with appropriate prior consultations,” the department said Thursday in its semiannual foreign-exchanges report. "Japan is transparent with respect to foreign exchange operations.”