North Korea fired off at least one ballistic missile on Saturday morning, amid a row between the two Koreas over a landmine explosion that injured three South Korean soldiers in the Demilitarized Zone last month.

The Defense Ministry in Tokyo said it had detected the launch of at least one missile from North Korea’s eastern coast that flew for an estimated 680 kilometers, hitting a maximum altitude of 90 km.

The missile had landed in waters of the Sea of Japan, outside 91AV原创 exclusive economic zone, which extends 200 nautical miles (370 kilometers) from its shores, according to the ministry.