SEOUL: North Korea fired three ballistic missiles toward the sea off its east coast on Thursday, South Korea said, in the latest such move by the isolated country racing to advance its weapons programmes on the day it first reported a COVID-19 outbreak.

Japan's coastguard confirmed the launch of a ballistic missile by North Korea, citing its military. The projectile appeared to fall outside Japan's exclusive economic zone, public broadcaster NHK said.

South Korea's Joint Chiefs of Staff said three short-range ballistic missiles were fired from the Sunan area of the North's capital, Pyongyang, where an international airport is located and where the North had said it fired its largest intercontinental ballistic missile (ICBM), the Hwasong-17, on March 24.

The missiles flew approximately 360 kilometres (224 miles), reaching an altitude of 90 km and a maximum velocity of Mach 5, the Joint Chiefs of Staff said.

North Korea fires likely submarine-launched ballistic missile, South Korea, Japan say

The firing was the first after the inauguration this week of conservative South Korean President Yoon Suk-yeol, who has signalled a hard line against the North's weapons development.

The launch, the North's 16th known weapons test this year, also came hours after it reported its first COVID-19 outbreak, declaring a "gravest national emergency" and ordering a national lockdown.

Yoon's national security office issued a statement condemning the launch and saying it "deplored the duplicitous conduct" of firing ballistic missiles and ignoring the plight of its people in the middle of a COVID outbreak.

In its last weapons test on Saturday, the North used a submarine-launched ballistic missile, which it has been aggressively developing in recent years.

North Korea reports first COVID-19 outbreak, orders lockdown in ‘gravest emergency’

North Korean leader Kim Jong Un vowed late last month to expedite the country's buildup of nuclear arsenal, amid stalled denuclearisation talks with the United States.

U.S. and South Korean officials have said Pyongyang's first nuclear test since 2017 could take place as early as this month.