SEOUL, Dec 18 (Reuters) - North Korea has fired a ballistic missile off its east coast, South Korea's military said on Monday.

Japan's defence ministry also said North Korea has fired what could be a ballistic missile.

No other details, including the missile's flight range, were immediately available.

The launch came just hours after North Korea fired a short-range ballistic missile on Sunday night, as it condemned U.S.-led military shows of force including the arrival of a submarine in South Korea as tantamount to "a preview of a nuclear war".