"We... condemn these missile launches and the DPRK's reckless decision to fire a missile below the de facto maritime boundary with the Republic of Korea," said White House national security spokesman John Kirby, referring to North and South Korea's official names, respectively.

Seoul's military said it was the "first time since the peninsula was divided" at the end of Korean War hostilities in 1953 that a North Korean missile had landed so close to the South's territorial waters.

Kirby said the missile launches did not pose any "immediate threat" to the United States or US personnel in the region.

However, he said, "these launches just underscore the need to make sure that we have the appropriate military readiness in and around the region."

US officials have said for months that Pyongyang is poised to undertake its first nuclear weapon test after a five-year hiatus.

Kirby said the United States continues to leave the door open to talks on denuclearizing the Korean peninsula, but Pyongyang has not responded and Beijing is not helping.

"We've been nothing but clear through diplomatic channels, but also publicly that we're willing to sit down with North Korea without preconditions to discuss the denuclearization of the peninsula," Kirby told reporters.

"We do know that Beijing has influence on Pyongyang. It may not be absolute influence, but they have influence," he said.

"And we've said many times that we would welcome Beijing to use the influence that they have in Pyongyang to a positive effect when it comes to the denuclearization of the peninsula."

"But we're not seeing that sort of influence being exerted by Beijing," he said.