U.S. Treasury Secretary Jack Lew and Finance Minister Taro Aso on Monday reaffirmed the importance of ensuring monetary policy is not aimed at manipulating exchange rates, the U.S. government said.

The Group of Seven (G-7) finance chiefs in the past agreed monetary measures should be solely aimed at boosting domestic economies without targeting any exchange rates, and Lew and Aso reaffirmed "the importance of abiding by G-7 agreements on exchange rates" in their talks in Istanbul.

The U.S. and Japanese finance chiefs met on the sidelines of a two-day meeting of the Group of 20 finance chiefs through Tuesday in the Turkish city.

Tokyo initially declined to confirm that Aso and Lew held talks even after the U.S. department released details of the meeting.

"There was an erroneous arrangement with the U.S. side" about publication of the meeting, an official from the Japanese delegation said.

Lew and Aso touched on the currency issue at a time when criticism is growing in Congress that Japan's monetary easing is being used to lower the value of the yen against the U.S. currency. Many American exporters have seen their profits decline on the back of the strong dollar.

They also talked about progress in negotiations for the 12-nation Trans-Pacific Partnership free trade initiative in which both countries are taking part, the U.S. Treasury Department said.

The 12 nations are hoping to seal the pact, which will cover some 40 percent of the global economy, later this year.

Lew and Aso discussed the performance of the global economy and the outlook for U.S. and Japanese economic growth as well, according to the department.