TOKYO Japan's business-to-business service prices rose 2.1% in August from a year earlier, accelerating from a 1.7% year-on-year gain in July, central bank data showed on Tuesday.

The Bank of Japan is closely watching service price movements to see whether inflationary pressure is broadening in the economy to warrant phasing out its massive stimulus.

(Reporting by Leika Kihara; Editing by Tom Hogue)