North Korea launched at least one ballistic missile Wednesday, Japan's Defense Ministry said, just hours after polls closed for midterm congressional elections in the United States.

The ministry said the missile had traveled 250 kilometers, hitting a maximum altitude of 50 km before falling into the Sea of Japan, outside Japan's exclusive economic zone, which extends 200 nautical miles (370 kilometers) from its coast.

South Korea's military also confirmed the launch of a short-range ballistic missile, saying it had been fired from the Sukchon area of South Pyongan Province.

Speaking to reporters shortly after the launch, the Japanese government's top spokesman, Chief Cabinet Secretary Hirokazu Matsuno, said no damage from the missile had been reported and that Tokyo was working to analyze the launch.

"North Korea's actions, including its repeated missile launches, threaten the peace and security of our region and the international community, and are absolutely unacceptable," Matsuno said, adding that Tokyo had lodged a stern complaint with the North through its embassy in Beijing.

The launch comes as U.S. states continued to count votes in Tuesday's midterm polls, in a crucial referendum on the administration of U.S. President Joe Biden.

It also comes on the heels of a flurry of more than 30 missile launches by the nuclear-armed country over the last week, including an apparent test of a new variant of intercontinental ballistic weapon that was believed to have failed over the Sea of Japan.

The ICBM test was initially believed to be headed over Japan, triggering a rare warning by the country’s J-Alert emergency broadcasting system that urged people to take shelter.

Last week, the U.S. and South Korean militaries concluded their large-scale Vigilant Storm joint air exercises, which involved around 240 aircraft, including advanced fighter jets and B-1B heavy bombers.

Pyongyang lambasted the exercises as an "open provocation aimed at intentionally escalating the tension in the region," vowing to continue to respond to any drills with "sustained, resolute and overwhelming practical military measures."

This has led some observers to conclude that North Korea could be laying the groundwork for conducting its seventh nuclear test and first since 2017, a move banned under United Nations sanctions.

South Korea, the U.S. and Japan have all said that Pyongyang has completed preparations for a blast, with Seoul's spy agency earlier saying the test could come before Tuesday's U.S. elections.

Anticipation of a nuclear test's timing has confounded observers after signs of the preparations emerged earlier this year, though many agree that it is a matter of "when," not "if" the country conducts a blast.

"I really don't get the fascination with trying to predict when #NorthKorea's next nuclear test will be," Jenny Town, director the North Korea-watching 38 North website, wrote on Twitter. "How has this been going on for so many months now? The reality is #DPRK does need to do additional testing to achieve the goals that they set. Not just one, but a few."

At a ruling party congress in January 2021, North Korean leader Kim Jong Un laid out an unusually detailed wish list of advanced new weaponry his country intended to build. This included smaller "tactical" nuclear bombs for use on the battlefield, as well as longer-range, solid-fuel and submarine-launched missiles and weapons capable of carrying multiple warheads.