In this photo provided by the North Korean government, North Korean leader Kim Jong Un, center, attends a meeting of the Central Committee of the ruling Workers' Party in Pyongyang, North Korea Thursday. Independent journalists were not given access to cover the event depicted in this image distributed by the North Korean government. The content of this image is as provided and cannot be independently verified. Korean language watermark on image as provided by source reads: "KCNA" which is the abbreviation for Korean Central News Agency. Korea News Service via AP

North Korea fired three short-range ballistic missiles from an area near Pyongyang toward waters off its east coast, South Korea said, the latest in a series of volleys ahead of a planned visit to the region next week by U.S. President Joe Biden.

Launched at 6:29 p.m. local time Thursday, the missiles flew about 224 miles and reached an altitude of 60 miles, South Korea’s Joint Chiefs of Staff said, adding it was still analyzing details.

It was North Korea’s third volley of ballistic missiles this month, and came before Biden is due to meet new South Korean President Yoon Suk-yeol on a trip that starts on May 20 to discuss policy toward the northern neighbor. Yoon has pledged to take a tough line with North Korea and the launch provides an early test of his government, which took office on Tuesday.

South Korea’s presidential office, which convened a security meeting immediately after the missile launch, said in a statement that it “strongly regrets” North Korea’s hostile behavior and added it would take “stern measures” in response.

North Korea appears to have fired the missiles from a large multiple rocket launcher at intervals of approximately 20 seconds, South Korean media including Yonhap reported, citing people they didn’t identify. They were also detected by Japan’s defense ministry. The missiles likely touched down outside of Japan’s exclusive economic zone, Japanese broadcaster NHK reported, citing an unidentified Japanese official.

The launch also came hours after leader Kim Jong Un ordered a lockdown following the country’s first reported case of COVID-19. Health experts have doubted North Korea’s claims of having escaped the coronavirus. Yang Moo-jin, a professor at the University of North Korean Studies in Seoul, said its announcement Thursday of its first case may be a way for Kim to signal that his regime is willing to open a channel for humanitarian assistance with the outside world.

Last Thursday, North Korea launched what appeared to be a medium-range ballistic missile, followed by the firing of a submarine-launched ballistic missile Saturday. Kim is on pace for his busiest year of ballistic missile launches since he took power a decade ago.

Over the past several months, Kim’s regime has tested a variety of missiles designed to evade U.S.-operated interceptors and increase the threat of a credible nuclear strike against the U.S. and its allies in Asia.