By Leika Kihara

TOKYO (Reuters) -The Bank of Japan said uncertainty over Japan's economy was growing as some firms worried about the hit to profits from higher U.S. duties, a sign that President Donald Trump's sweeping tariffs risk upending a moderate economic recovery.

One of the BOJ's branch managers described the Trump-induced turmoil as "unlike any other shock" with the impact on the economy hard to quantify, suggesting the uncertainty will keep the central bank in a holding pattern for the time being.

In a quarterly meeting of its regional branch managers on Monday, the BOJ maintained its assessment for all nine regions of the country to say they were either recovering or picking up moderately.

But it said in a statement that "uncertainty over Japan's economy was heightening," underscoring its concern that Trump's tariffs could derail a cycle of rising wages and prices - a key prerequisite for further interest rate hikes.

While it did not directly mention higher U.S. tariffs, it warned that "some firms voiced concern over the impact on output and profits" from U.S. trade uncertainty.

BOJ Osaka branch manager Kazuhiro Masaki said Trump's reciprocal tariffs were likely to have a negative impact on corporate sentiment, adding that companies in western Japan were already brainstorming ways to cope with downside risks.

"This shock is unlike any other shock in the past in that it is policy-driven. It's thus hard to examine the potential impact based on past experiences," Masaki told a news conference.

"The impact could come through many channels including through trade and market moves," said Masaki who, before assuming the current post, was head of the BOJ's division drafting monetary policy.

The branch managers of central and southern Japan, home to auto giants like Toyota Motor and its suppliers, also warned of the potential impact from tariffs.

"Firms were already warning of uncertainty over their earnings in March. I expect such views to spread," Kenji Sakuta, the BOJ's Fukuoka branch manager, told a news conference.

MARKET TURMOIL

The BOJ's assessment of regional economies will be among factors that will be scrutinised at its next policy meeting on April 30-May 1, when the board is seen keeping interest rates steady at 0.5% and issuing fresh quarterly economic forecasts.

Asian share markets tanked on Monday as investors feared that Trump's tariffs could lead to higher prices, weaker demand and tip the global economy into recession.