The Bank of Japan cut its assessment for three of the country's nine regions, the biggest number of downgrades in six years.

BOJ Governor Haruhiko Kuroda said the economy was expected to continue expanding moderately with robust domestic demand offsetting some of the weaknesses in exports.

But the central bank warned that weakening global growth and simmering Sino-U.S. trade tensions were taking a toll on some Japanese regions reliant on overseas demand.

"We have had to cut our assessments on exports and output for some regions because we're hearing more complaints about the impact of the global economic slowdown than three months ago," said BOJ.

The report cited several companies that put off investment in new equipment due to uncertainty over the global outlook.

The BOJ raised its assessment for one region, while it maintained its view for five regions.