A missile that analysts believe could be the North Korean Hwasong-12 is paraded across Kim Il Sung Square in Pyongyang. File/AP
The last time North Korea fired a missile over Japan was in 2017, at the height of a period of "fire and fury" when Pyongyang's leader Kim Jong Un traded insults with then-US president Donald Trump.
South Korea's military said it had detected the launch of an IRBM, which flew around 4,500 kilometres (2,800 miles) at an altitude of about 970 kilometres and a speed of around Mach 17.
"Specific details are under close analysis by South Korean and US intelligence," the South's Joint Chiefs of Staff added in a statement.
South Korea's President Yoon Suk-yeol called the launch a "provocation" that violated UN regulations.
A big screen shows North Korea's leader Kim Jong Un in a news report in Tokyo, Japan, on Tuesday. Reuters
Yoon "ordered a stern response and to take corresponding measures in cooperation with the United States and the international community", his office said in a statement.
North Korea was not responding to routine daily contact on the inter-Korean liaison line Tuesday, Seoul's unification ministry said.
Tokyo also confirmed the launch of an IRBM, activating the country's missile alert warning system and urging people to take shelter.
"North Korea appears to have launched a missile. Please evacuate into buildings or underground," the government said in an alert issued at 7:29 am (2229 GMT Monday).
Prime Minister Fumio Kishida told reporters that the launch was "an act of violence following recent repeated launches of ballistic missiles. We strongly condemn this."
People walk in front of a screen showing a news report about North Korea firing a missile over Japan in Tokyo. Reuters
Defence Minister Yasukazu Hamada said that North Korea "has in the past launched Hwasong 12-type missiles four times, so this could be the same type".
If so, the flight distance, which Tokyo estimated at 4,600 kilometres, was thought to be a new record for that particular type of missile.
The last two times North Korea fired Hwasong-12 missiles over Japan, in September and August 2017, they travelled 3,700 kilometres and 2,700 kilometres respectively, Chad O'Carroll of Seoul-based specialist site NK News wrote on Twitter.
"This is the 8th test of the Hwasong-12 and the 3rd time it has overflown Japan," Jeffrey Lewis of the Middlebury Institute of International Studies wrote on Twitter.
Washington condemned the launch, with US National Security Advisor Jake Sullivan speaking to his counterparts in Seoul and Tokyo to discuss an "appropriate and robust" joint response.
"Sullivan reinforced the United States' ironclad commitments to the defense of Japan and the ROK (South Korea)," national security spokeswoman Adrienne Watson said in a statement.
With talks long-stalled, nuclear-armed North Korea has doubled down on Kim's military modernisation plans this year, testing a string of banned weaponry, including an intercontinental ballistic missile (ICBM) also for the first time since 2017.
Last week, Pyongyang fired short-range ballistic missiles on four occasions, including just hours after US Vice President Kamala Harris flew out of Seoul.
Pyongyang's latest bout of intense weapons testing comes as Seoul, Tokyo and Washington ramp up joint military drills to counter growing threats from the North.
South Korea, Japan and the United States staged anti-submarine drills Friday — the first in five years — just days after Washington and Seoul's navies conducted large-scale exercises in waters off the peninsula, involving a nuclear-powered US aircraft carrier.
Such drills infuriate North Korea, which sees them as rehearsals for an invasion.
Harris toured the heavily fortified Demilitarized Zone that divides the peninsula while on a trip that aimed to underscore her country's "ironclad" commitment to South Korea's defence against the North.
Washington has stationed about 28,500 troops in South Korea to help protect it from the North.
Firing a missile over Japan represented a "significant escalation" by North Korea, said Leif-Eric Easley, a professor at Ewha University in Seoul.
Japanese Defence Minister Yasukazu Hamada (centre) speaks to the media in Tokyo on Tuesday. AP
"Pyongyang is still in the middle of a provocation and testing cycle," he added.
"The Kim regime is developing weapons such as tactical nuclear warheads and submarine-launched ballistic missiles as part of a long-term strategy to outrun South Korea in an arms race and drive wedges among US allies."
South Korean and US officials have also been warning for months that Kim is preparing to conduct another nuclear test, saying last week that this could happen soon after China's upcoming party congress on October 16.
North Korea, which is under multiple UN sanctions for its weapons programmes, typically seeks to maximise the geopolitical impact of its tests with careful timing.
The isolated country has tested nuclear weapons six times since 2006, most recently in 2017.
North Korea’s state media on Saturday lashed out at Japanese Prime Minister Shinzo Abe as an “imbecile and political dwarf” for calling Pyongyang’s latest test of a large multiple-rocket launcher
The string of weapons drills come as a prolonged hiatus in disarmament talks with the United States drags on, and despite recent overtures from Washington offering help to contain the pandemic.
Japan has raised its caution level about North Korea’s missile capability, saying in a defense report that the country resumed missile tests while taking no concrete denuclearization steps
One ballistic missile was launched about 10:17am local time from the vicinity of Sinpo, South Korea's Joint Chiefs of Staff said, where North Korea keeps submarines as well as equipment for test firing submarine-launched ballistic missiles (SLBMs).
The "Grain from Ukraine" initiative demonstrated global food security was "not just empty words" for Kyiv, he said. The Kremlin says food exported from Ukraine's Black Sea ports under a UN-brokered plan has not been reaching the most vulnerable countries.
At the tall candle-shaped Holodomor (Ukrainian for death by starvation) memorial centre in central Kyiv, a dozen Orthodox priests in black and silver robes gathered Saturday for a religious ceremony for the victims of the famine.
Russian forces completed their withdrawal from the city of Kherson on Nov. 11 after an almost nine-month occupation. They are now positioned on the eastern bank of the Dnipro, from where they have been shelling the city regularly.