The NSC meeting was convened shortly after the communist North launched an apparent ballistic missile into the East Sea.

Seoul's Joint Chiefs of Staff earlier said the projectile flew some 930 kilometers.

"North Korea's nuclear weapons and missiles are a matter of our life or death that threatens the very safety and lives of our people and our allies," Moon said. "We will not tolerate any such threat under any circumstances."

The latest North Korean missile launch, the sixth of its kind since Moon took office May 10, came shortly after he returned home from a visit to Washington, where he and his US counterpart, Donald Trump, agreed to seek a phased denuclearization of the North, enabling a resumption of dialogue with the reclusive state following its initial steps to denuclearize.

"I express a deep disappointment and regret over the fact that North Korea staged such a provocation only a few days after President Trump and I urged North Korea to reduce its provocations, refrain from military actions that cause instability and make a strategic decision to abide by international duties and regulations," Moon told the NSC meeting he chaired.

"Our government will resolutely deal with North Korean provocations in close cooperation with the international community while maintaining a strong joint defense posture of the Korea-US

joint forces based on the strong Korea-US alliance," he added.

Regarding the North Korean projectile launched Tuesday, the South Korean president said it appeared to be an intermediate range missile, but that it was too early to rule out the possibility of it being an intercontinental ballistic missile.

"We plan to devise necessary measures assuming it may have been an ICBM," he said. (Yonhap)