It said it was analyzing what type of missile North Korea launched.
Japanese authorities provided backing the South's report, with Kyodo News saying it believed the test may have failed.
Chief Cabinet Secretary Yoshihide Suga said the government had not confirmed whether the missiles were trying to be fired towards Japan.
'US Pacific Command detected what we assess was a failed North Korean missile launch attempt ... in the vicinity of Kalma,' a spokesman for US Pacific Command, Commander Dave Benham, said.
'A missile appears to have exploded within seconds of launch," the Daily Mail cited him a saying.
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