North Korea test launched a suspected intercontinental ballistic missile and two weapons with a shorter range into the sea on Wednesday.
All three missiles were fired from near Pyongyang off the eastern coast between 6am and 7am on Wednesday, according to South Korea’s Joint Chiefs of Staff.
The suspected ballistic missile reached a height of 540km (335 miles) and travelled 360km (223 miles) east after it was fired from Pyongyang.
A statement from the South Korean government said: “North Korea’s sustained provocations can only result in stronger and faster South Korea-U.S. combined deterrence and can only deepen North Korea’s international isolation.
“(Our) government is maintaining constant readiness to strongly and effectively respond to any kind of North Korean provocation.
Authorities in Seoul said the missiles were fired in less than an hour from the Sunan area of Pyongyang.
President Biden’s trip to Asia included a summit with South Korean President Yoon Suk-yeol in Seoul, where they agreed to hold military drills and deploy more US strategic assets if required to deter North Korea from intensifying its weapons tests.
The Japanese Defence Minister, Nobuo Kishi, described the launches as “an act of provocation and absolutely impermissible”.
He accused Pyongyang of pursuing its weapon development programme while “ignoring the people’s suffering amid the spread of the coronavirus in the country”.
The missile launch has come at a time when North Korea is making a controversial claim its domestic COVID-19 outbreak is weakening.
Leif-Eric Easley, associate professor of international studies at Ewha University in Seoul, said: “If Omicron is raging in the country, it is not the best time for Kim to take domestic political credit for a nuclear test.
“So declaring victory against COVID, at least in state propaganda, will probably come first. But North Korea is likely to conduct its seventh nuclear test before reengaging in diplomacy.”
President Biden has warned North Korea the US is “prepared for anything North Korea does”.