The United States understands Japan's intervention in the foreign exchange market amid the yen's rapid decline against the U.S. dollar, a Treasury Department official said Thursday.

But the official denied that the United States was involved in the dollar-selling, yen-buying intervention earlier Thursday, Tokyo's first such operation in 24 years.

"We understand Japan's action, which it states aims to reduce recent heightened volatility of the yen," a Treasury spokesperson said in an email.

Japan conducted a large-scale yen-buying operation Thursday after the dollar rose above the 145 yen line in Tokyo trading, its highest level since 1998.

Photo taken on Sept. 22, 2022, shows the U.S. Treasury building in Washington. (Kyodo)

The intervention briefly brought the U.S. currency down by about five yen to the 140 yen range, but its effect on stemming volatility may be limited as the operation was carried out unilaterally by Japan.

"We did not participate in the intervention," the spokesperson said. A European Central Bank official also denied involvement.

Earlier, Japanese Finance Minister Shunichi Suzuki declined to comment on whether Tokyo had coordinated with other countries on the move.

On Friday in London, the dollar traded around 143 yen, compared with 142.35-45 yen in New York at 5 p.m. Thursday.

Prime Minister Fumio Kishida suggested Thursday that Japan may intervene in the market again if necessary, saying the country will "continue to take decisive steps against excessive currency moves."

"We cannot overlook the ongoing volatility based on speculation," Kishida said on the sidelines of the U.N. General Assembly in New York.

Behind the yen's fall since early March is the Bank of Japan's stance of maintaining its ultraeasy monetary policy at a critical time when the U.S. Federal Reserve and central banks in many other countries are hiking rates to beat inflation.

The last time Japan intervened in the currency market to buy the yen was in 1998 when the country's economy experienced a slump after the consumption tax was raised to 5 percent from 3 percent the previous year.

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