South Korea's military confirmed on Saturday that North Korea had launched a ballistic missile from a submarine, while Pyongyang vowed to develop its nuclear forces "as quickly as possible."
South Korea's military said Pyongyang had fired a missile off its east coast, and Yonhap news agency said the military believed it was a ballistic missile.
Japan's Defense Ministry said on Twitter that the missile could be a ballistic missile.
South Korea and Japan said North Korea launched a ballistic missile on Wednesday into the sea off its east coast, after Pyongyang pledged to develop its nuclear forces "as quickly as possible".
ballistic missile tests
North Korea recently ramped up weapons tests, and resumed intercontinental ballistic missile tests this year for the first time since 2017.
North Korea has not tested a nuclear bomb since 2017, but US and South Korean officials have been saying for weeks that there are indications of new construction at Punggye-ri, the North's only known nuclear test site, and that North Korea may soon test another bomb.
The Bunge-ri site has been officially closed since 2018. And Porter's statement that the site could be ready this month is more specific about a possible time for a test, the first recorded statement of its kind by a US official.
Galina Porter, deputy spokesman for the US State Department, said Friday that US assessments indicate that North Korea is preparing the Punggye-ri nuclear test site, and that it may be ready to conduct a nuclear test there this month.
"The United States estimates that the Democratic People's Republic of Korea is preparing the Punggye-ri test site and may be ready to conduct a test there this month at the latest, and it will be its seventh," she added.
"This assessment is consistent with recent public statements by North Korea. We have shared this information with allies and partners and will continue to coordinate closely with them."
Last week, North Korean leader Kim Jong Un vowed to speed up the development of his country's nuclear arsenal while attending a massive military parade as talks on denuclearization remained stalled with the United States.
