"North Korea launched an ICBM-class ballistic missile from near the western coast of the Korean Peninsula at around 10:14 (0114 GMT) today," it said in a statement.

"Details are being analysed, but the fired ballistic missile is currently flying and may fall into the Sea of Japan within Japan's exclusive economic zone (EEZ)."

Japan's coastguard, citing the defence ministry, said the missile was expected to fall in the waters around 210 kilometres (130 miles) west of Oshima Oshima Island off Hokkaido in Northern Japan at around 11.20 am (0220 GMT), but there was no immediate confirmation it had landed.

It was Pyongyang's second launch in two days as the isolated state continues a record-breaking blitz that has sent fears of a nuclear test soaring.

A South Korean defence official told AFP they "estimated that North Korea had fired an ICBM", without giving further details.

Seoul's Joint Chiefs of Staff earlier said it had detected the "launch of an unidentified ballistic missile in an eastward direction".