Matthew Galat, a US citizen staying near Lake Toya in the Japanese island of Hokkaido, said he had been 'abruptly' woken up by 'a loud noise on my phone', calling it a 'nice wake up call'.
Millions of people in northern Japan were woken up by a wail of sirens warning them a North Korean missile was heading in their direction.
A text alert saying 'Missile launch! Missile launch!' was sent to residents as they were woken by loudspeakers and urged to 'take cover in a building or underground'.
Breakfast TV shows also flashed with the warning: 'Flee into a building or a basement.'
North Korea's proximity means that Japanese authorities realistically have less than 10 minutes to confirm a missile launch and issue the alerts.
Millions of Japanese were jolted awake by blaring sirens and emergency text message alerts
Breakfast TV shows this morning flashed with the warning: 'Flee into a building or a basement'
Aftermath: Pedestrians in Tokyo walk under a large-scale monitor displaying North Korean leader Kim Jong-un on a TV news broadcast after the launch ballistic missile over Japan on Friday morning, which travelled 2,300 miles
Seven minutes later, a second text confirmed the missile had passed over Japanese territory without incident before splashing into the Pacific ocean 2,000km to the east. 'Missile passed. Missile passed,' it said.
'It seems that the missile has passed Hokkaido area and landed in the Pacific Ocean. If you find anything suspicious, please don't go close to it. Report it to the police and firefighters.'
Matthew Galat, a US citizen staying near Lake Toya in the Japanese island of Hokkaido, said he had been 'abruptly' woken up by 'a really loud noise on my phone', calling it a 'nice wake up call'.
It sent out two loud alarms on his phone despite it being turned to silent. He said there was one at 7am and then another at 7.07am (local time).
'This loud speaker is playing all throughout the city,' Galat said in a Facebook video recorded while the sirens were still sounding.
The vlogger, who is cycling around the world from China to the US, said the alert, which he translated into English on his smartphone, told him to find shelter in a basement because North Korea had just launched a missile. 'Crazy…stupid,' he said.
He added: 'People are pretty subdued here...there wasn't anyone exactly looking panicked but I talked to the owner of the hotel and we were marveling at what had happened and what we are in the middle of.'
Yoshihiro Saito, who works in the small Hokkaido fishing town of Erimo, said: 'I cannot say that we are used to this.
'I mean, the missile flew right above our town. It's not a very comforting thing to hear. It's pretty scary.'
North Korea fired a ballistic missile over Japan and into the Pacific Friday, responding to new UN sanctions with its furthest-ever missile flight in what analysts called a demonstration of its ability to target Guam
After receiving his second warning in a little over two weeks, Yoichi Takahashi questioned the government's advice.
'It's really scary. The government tells us to flee to stable buildings but we can't do that quickly,' said the 57-year old fisheries official in the Hokkaido town of Kushiro.
'Our colleagues offshore can never take cover. It has now happened twice to us...we're going to have restless days from now on.'
Prefectural emergency official Shuji Koshida said the response went relatively smoothly.
'We could spring into action after the first alert this time,' he said. But he added, 'We hope missiles are not launched from North Korea to begin with.'
Officials say there is little more that towns can do to prepare, except for raising public awareness about how to respond.
The alert also disrupted play at an international golf tournament in Sapporo.
Matt Griffin, an Australian golfer, said he was in his hotel room when he received the text alerts.
He said: 'Well this is a first. We currently have a suspension of play in Sapporo Japan due to North Korea launching ballistic missiles.'
The launch, from near Pyongyang, came after the UN Security Council imposed an eighth set of measures on the isolated country following its sixth nuclear test earlier this month
The missile reached an altitude of about 770km (478 miles), travelling 3,700km before landing in the sea off Hokkaido, South Korea's military says.
It flew higher and further than one fired over Japan late last month.
Japanese Prime Minister Shinzo Abe said Tokyo could 'never tolerate' what he called a 'dangerous provocative action that threatens world peace'.
'If North Korea continues to walk down this path, it has no bright future,' he told reporters. 'We must make North Korea understand this.'
South Korea responded within minutes by firing two ballistic missiles into the sea in a simulated strike on the North.
US Defense Secretary James Mattis said Pyongyang had forced 'millions of Japanese into the duck and cover', while Secretary of State Rex Tillerson urged China and Russia, Pyongyang's main defenders, to take 'direct actions' to rein it in.
Beijing said it opposed the launch, with foreign ministry spokeswoman Hua Chunying adding China would 'continue to comprehensively and completely implement' UN sanctions resolutions.
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