South Korea’s Joint Chiefs of Staff reported the launch early Sunday as a US aircraft carrier has arrived in the country to participate in joint drills with South Korean forces, and days before a planned visit by US Vice President Kamala Harris.
Japan’s public broadcaster NHK also said the object appeared to have fallen outside the country’s exclusive economic zone.
Hours later, South Korea said the North had launched one short-range ballistic missile from near its capital city, Pyongyang.
Japan Defense Minister Yasukazu Hamada said the North Korean missile reached an altitude of 50 kilometers and it may have flown on an irregular trajectory.
“If you include launches of cruise missiles this is the nineteenth launch, which is an unprecedented pace,” he added.
South Korea’s military, however, said it was a single, short-range ballistic missile fired from near the Taechon area of North Pyongyan Province just before 7 a.m. local time and flew about 600 km (373 miles) at an altitude of 60 km and a speed of Mach 5.
The new missile firing came more than a month after North Korea fired two cruise missiles toward the sea off its west coast in mid-August.
It was Pyongyang’s first weapons test since early July, and came a day after South Korea and the United States began a four-day preliminary joint drill.
Pyongyang has frequently protested against joint military exercises involving Seoul and Washington, calling them rehearsals for invasion despite Washington’s mantra of diplomacy.
South Korea’s hawkish President Yoon Suk-yeol, who took office in May, has vowed to beef up joint military exercises with the United States, after years of failed diplomacy with North Korea under his predecessor.
The two countries have long carried out joint exercises, which they insist are purely defensive, but North Korea sees them as rehearsals for an invasion.
The drills have also been criticized by Russia and China, which have called on all sides not to take steps that raise tensions in the region, and have called for an easing of sanctions.
North Korea has test-fired a record number of missiles this year amid claims by officials in Seoul and Washington that Pyongyang appears to be preparing to test a nuclear weapon for the first time since 2017.
North Korea conducted its sixth nuclear test in September 2017. However, during inconclusive negotiations later with the US, it dismantled a nuclear facility and has not conducted any other nuclear tests since then.
The United States has warned that it would push for additional sanctions if Pyongyang conducted a seventh nuclear test.
The North’s leader Kim Jong-un has said that his country is “ready to mobilize” its nuclear deterrent in any future military conflict with the United States and Seoul.