Japan's top currency diplomat Masato Kanda said Wednesday the yen's fall has been "very rapid" and driven in part by speculative moves, warning the government will respond "appropriately" if required.

The remarks came after the U.S. dollar hit a three-month high of 150.88 yen overnight, as stronger-than-expected U.S. inflation data reduced market expectations of an interest rate cut by the Federal Reserve.

The yen's fall "has been very rapid, which will negatively impact the economy," Kanda, vice finance minister for international affairs, told reporters. The Japanese currency "has weakened nearly 10 yen (against the dollar) over the past month."

Japanese officials issue verbal warnings when currency movements are volatile, before actually intervening in the foreign exchange market to rectify rapid shifts viewed as not reflecting economic fundamentals.

Japan repeatedly stepped into the market by buying the yen for the dollar in 2022 but has since stayed out.

The weaker yen dealt a blow to resource-scarce Japan by boosting the value of imported energy and raw materials, accelerating inflation.

The yen's renewed weakness comes as financial markets are expecting the Bank of Japan, which has been deeply committed to monetary easing, to scrap its negative interest rate policy in the coming months.

BOJ chief Kazuo Ueda has said monetary conditions will remain "accommodative" even if the negative rate ends, a stance that has apparently supported Japanese stocks and yen weakness.

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