In what is being called a clear message of defiance to its rivals, North Korea has fired a second missile across northern Japan, accomplishing its longest flight distance yet.
The move follows the latest United Nations sanctions, and the UN Security Council quickly called another emergency meeting.
South Korea's reaction was to immediately launch live fire drills.
The skies of the Korean Peninsula have filled once more with soaring weaponry.
South Korea has conducted a live-fire, ballistic-missile drill immediately after North Korean leader Kim Jong-un's latest show of his country's growing missile capabilities.
The South's military manoeuvre was a clear show of combat readiness against the North's relentless tests.
Earlier in the day, people in northern Japan had awoken to blaring alerts that North Korea was about to fire a missile over Japan for the second time in less than three weeks.
The missile was launched from the Sunan district of North Korea's capital, Pyongyang, just before 7am Japanese time.
Japanese officials say it reached an altitude of about 770 kilometres and flew for 19 minutes before landing about 2,000 kilometres east of Hokkaido.
It followed a similar path to the missile fired last month, but the South Korean military says this one flew higher and further, a distance that could reach the island of Guam.
Guam is a United States territory in the Pacific Ocean, and US president Donald Trump has threatened a massive retaliation if North Korea fires a missile to that area.
Japanese prime minister Shinzo Abe has called the latest launch unacceptable.
"The international community needs to come together and send a clear message to North Korea that it's threatening world peace with its actions."
The previous night, North Korea had threatened to sink Japan and reduce the United States to what it called "ashes and darkness."
That threat followed a new round of unanimously approved sanctions in the United Nations Security Council.
Textile exports are now banned, and imports of crude oil have been capped.
In Australia, Prime Minister Malcolm Turnbull is among those viewing the new missile launch as a direct response to the sanctions.
"The economic screws are tightening on North Korea. The critical thing is to continue to apply economic pressure on North Korea to bring the regime to its senses. Nobody wants to see a war on the Korean Peninsula."
Hours before the launch, US Secretary of State Rex Tillerson had called on China to reconsider supplying North Korea with most of its oil.
"I am hopeful that China, as a great country, a world power, will decide on its own and will take it upon themselves to use that very powerful tool of oil supply to persuade North Korea to reconsider its current path towards weapons development, reconsider its approach to dialogue and negotiations in the future."
South Korea appears to have given up on dialogue with its counterpart across the border.
President Moon Jae-in has declared the circumstances "impossible."
"The government will make efforts to tightly protect our country from North Korea's threats with our own military power and joint defence capabilities. We have powers to annihilate it at an early stage and give it a crushing defeat."
