Asked about her thoughts on Japan's possible steps in response to the yen's depreciation against the dollar, U.S. Treasury Secretary Janet Yellen said intervening in foreign exchange markets should be rare.

Yellen said in a live interview with Reuters on Thursday that from G7 countriesplaypokergamesFrom the perspective of thinking,"Exchange rate adjustment in the market is one of the foundations for countries to have different policies." For "large countries with market-determined exchange rates", intervention should occur only in extremely rare circumstances.

"We would hope that it would be rare, and we would also think that this intervention would be rare and only occurs in excessive fluctuations, andplaypokergamesThey will consult in advance,"Yellen said.

The yen's fall to its lowest point against the U.S. dollar in decades has attracted the attention of Japanese authorities and said they reserve the right to intervene in the market. The yen fell below 155 against the dollar on Wednesday, raising the risk that this key level could prompt Japanese authorities to enter the market.

Yellen would not comment on a reasonable valuation of the yen.