The missiles were launched from the eastern province of Kangwon at 6.49 am and travelled roughly 250 km before plunging into the sea, according to South Korea's joint chiefs of staff, Efe reported.
The US Pacific Command confirmed the launches, adding that "the first and third missiles failed in flight", while the second "appears to have blown up almost immediately".
The statement added that the launches "did not pose a threat to North America" or Guam.
The launch comes as the US and South Korean armies are conducting annual joint military drills known as "Ulchi Freedom Guardian" in South Korea, which began on Monday.
It was not immediately clear whether the missiles were short or long range.
South Korea's presidential office has convened a meeting of its National Security Council to discuss the matter.
The launch is the first since a nocturnal test was carried out on July 28, in which an intercontinental ballistic missile was fired into the Sea of Japan, provoking a new round of UN sanctions and rebukes from the international community.
North Korea responded by threatening to bomb the waters surrounding the US territory of Guam, which led to one of the most serious escalations in hostile rhetoric between Washington and Pyongyang in recent years.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
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