TOKYO, May 28 (Reuters) - The Bank of Japan's four key measurements of underlying inflation all fell below 2% in April for the first time since August 2022, data showed on Tuesday, heightening uncertainty on the timing of its next interest rate hike.

The weighted median inflation rate, among the four indicators closely watched as a gauge on whether price rises are broadening, rose 1.1% in April from a year earlier, the data showed.

(Reporting by Leika Kihara and Takahiko Wada; Editing by Christian Schmollinger)