Japanese Finance Minister Shunichi Suzuki said Friday the government is closely monitoring developments in the foreign exchange market after the yen rose sharply against the U.S. dollar on market speculation of a policy change by the Bank of Japan.

Suzuki declined to say how Japanese authorities would respond, as his comments could sway forex markets.

Photo taken in Tokyo on Dec. 8, 2023, shows monitor screens displaying the Japanese yen trading in the 141 zone against the U.S. dollar. (Kyodo)

The yen rose sharply to 141.60 per U.S. dollar, the highest in four months, overnight after BOJ chief Kazuo Ueda said Thursday he expects a "challenging" time toward next year, a remark interpreted by financial markets to mean the BOJ is set to tighten monetary policy.

Ueda made the remarks at an upper house committee after the bank in late October stuck to its ultralow rates but decided to allow long-term government yields to rise above its previously rigid ceiling of 1.0 percent.

The BOJ has been out of step with its global peers, including the U.S. Federal Reserve and the European Central Bank, which have hiked rates aggressively to fight inflation.

Related coverage:

Japan's economy shrinks 2.9% in July-Sept., revised down