SEOUL, Feb 22 (Reuters) - South Korea's central bank left interest rates at a 15-year high on Thursday amid signs that the weaker economy is slowing inflation.

The Bank of Korea (BOK) held its key policy rate at 3.50% at a policy review in Seoul, keeping it unchanged for a ninth straight meeting as expected by all 38 analysts polled by Reuters.

Governor Rhee Chang-yong will hold a news conference at around 0210 GMT, which will be livestreamed via YouTube.

(Reporting by Cynthia Kim; Editing by Sam Holmes)