The missile launches on Wednesday were a strong signal that North Korea was embarking on a new cycle of tensions in the Korean Peninsula despite the country’s first reported outbreak of the coronavirus. It also constituted North Korea’s public reaction to Mr. Biden’s trip to the region, where he met with the leaders of South Korea and Japan and vowed to step up measures, including joint military exercises, to help deter the growing nuclear and missile threat from the North.
The country has also been conducting high-explosive tests in recent weeks, indicating that a nuclear test may be imminent, Mr. Kim, the South Korean presidential aide, said on Wednesday. High explosives are used to help trigger fission in a nuclear device, and North Korea has conducted dozens of high-explosive tests over the years.
In a meeting with Mr. Yoon in Seoul last Saturday, Mr. Biden said that the United States would bolster the alliance and increase deterrence in the face of the North Korean threat. Mr. Biden and Mr. Yoon announced that they would explore ways to expand joint military exercises that had been canceled or scaled down under President Donald J. Trump.
While in South Korea, Mr. Biden voiced a deep skepticism about the chances of meeting North Korea’s leader, Kim Jong-un, whom Mr. Trump met three times. Asked by reporters if he had a message for Mr. Kim, Mr. Biden said simply: “Hello. Period.”
Mr. Yoon has been highly skeptical of North Korea, as well, saying that the efforts by his predecessor, Moon Jae-in, to engage with the North in dialogue and reconciliation have failed to roll back its nuclear weapons program.
When Mr. Yoon was sworn into office on May 10, he dangled “an audacious plan” to vastly improve the North’s economy and its people’s quality of life. But like his conservative predecessors, he attached an important caveat: Such economic largess would be possible only “if North Korea genuinely embarks on a process to complete denuclearization.”
The missile tests on Wednesday indicated that North Korea was not interested in nuclear disarmament talks anytime soon. In a speech delivered during a nighttime military parade in April, North Korea’s leader, Kim Jong-un, reiterated that his people should prepare for a standoff with the United States “for a long period of time.” He also vowed to expand his arsenal of nuclear warheads, intercontinental ballistic missiles and other delivery vehicles “at the fastest possible speed.”