Significantly the test appeared to have struck near the eastern coast of Russia, which prompted a reaction on Monday from Russian President Vladimir Putin.
North Korean state media KCNA claimed that the apparently new Hwasong-12 missile reached an altitude of 2,111.5 kilometers (1,312 miles). If confirmed, that would make it the highest test out of the seven Pyongyang has conducted this year.
What's worrying to the United States, among other countries, is that if this missile were fired at a different trajectory, it could have reached the US Andersen Air Force Base in Guam, according to aerospace engineer John Schilling's 38 North blog, which is published by the US Korea Institute at Johns Hopkins University.
Guam is situated around 3,500 kilometers (2,200 miles) southeast of North Korea. And the US rotates heavy bombers, including B-1s, B-2s and B-52s, through the island.
"North Korea's latest successful missile test represents a level of performance never before seen from a North Korean missile," Schilling wrote.
Pyongyang has long threatened to develop a nuclear-tipped missile that could reach the United States, a distance of around 8,000 km (4,800 miles). But Tong Zhao, an analyst with the Carnegie-Tsinghua Center for Global Policy, said Sunday's test may give Pyongyang "a regional nuclear deterrence" option, meaning it might no longer need to pursue a weapon to reach as far as the US mainland.
The US military's Pacific Command said the type of missile fired was "not consistent" with an intercontinental ballistic missile (ICBM), according to Reuters reports.
But Melissa Hanham, senior research associate at the James Martin Center for Nonproliferation Studies in California, said the test could just as easily be a stepping stone to a longer-range weapon.
"This may become half or a third of an ICBM," she said, pointing out that such missile are built in two or three stages stacked atop of each other.
Sunday's test is also the first from North Korea since South Korean President Moon Jae-in took office last week. Moon has advocated dialogue with North Korea to denuclearize.
In response, Moon said the missile test violates UN Security Council resolutions and called it a severe challenge to the peace and security of the Korean Peninsula and the world.
Could North Korea launch a nuclear missile?
North Korean state media claimed that Sunday's test proved that the country could launch a missile with a nuclear tip. While North Korean's arsenal of missiles is becoming clearer, there is less certainty about how developed its nuclear program is.
To actually deliver such a missile, Pyongyang would have to have advanced technology in both miniaturizing its nuclear weapons as well as in protecting a nuclear warhead from being destroyed upon re-entry in the earth's atmosphere.
North Korean state media claimed that Sunday's test verified a homing feature in the missile that allowed it to survive "under the worst re-entry situation" and accurately detonate. But that claim has not yet been verified by experts or officials in other countries.
"It's a challenging form of technology, and there's no indication yet in the public realm that North Korea has it," Martin Navias from the Center for Defense Studies at Kings College London told CNN.
"If you think of a space vehicle re-entering the earth's atmosphere, they have heat protectors to stop it from burning up inside. The speed at which a missile comes through the atmosphere creates an enormous amount of air pressure and heat."
Will this provoke Russia?
Sunday's test missile flew 787 kilometers (489 miles) across North Korea and into the Sea of Japan, also known as the East Sea, according to state media, and it appeared to have struck near the eastern coast of Russia.
US officials said the missile hit the water around 60 miles (around 100 kilometers) from eastern Russia's Vladivostok. However, Russia said it fell 310 miles (500 kilometers) from its coast.
The White House condemned the attack and made an unusually speculative statement, saying that "the President cannot imagine that Russia is pleased."
On Monday, Russian President Vladimir Putin condemned the launch as "counterproductive, damaging, dangerous." But he warned against "intimidating" Pyongyang.
Russia initially responded to Sunday's test by putting its far eastern air defenses on high alert, according to Russian state media, and Putin reportedly discussed the launch with Chinese President Xi Jinping during a meeting in Beijing.
"Concern was expressed about the escalation of tension, including in connection with the launch (of the missile of the DPRK)," Kremlin spokesman Dmitry Peskov was quoted as saying in Russian state media.
The test is unlikely to mark a new phase in North Korea's missile and nuclear ambitions. Russia is one of the few countries that has diplomatic ties with North Korea.
Russia has shown concern about Pyongyang's missiles, but it may also see North Korea as an opportunity to gain leverage with the West, the US in particular, according to CNN Moscow Bureau Chief Matthew Chance.
"If Russia can be instrumental in resolving a key international dispute like North Korea, they will want to parry that into something else, to use it as a bargaining chip," he said.
What will the US do?
US President Donald Trump's administration has made North Korea a priority security issue. The US has sent warships and submarines to waters off the Korean Peninsula, engaged in drills with South Korean and Japanese forces, and has pushed for stronger economic sanctions on Pyongyang.
Following Sunday's test, the US called for repercussions from the international community.
"Let this latest provocation serve as a call for all nations to implement far stronger sanctions against North Korea," said the statement from White House press secretary Sean Spicer.
Trump has advocated for a diplomatic solution to the uptick in North Korean aggravations, but he said last month that he would not rule out a major conflict with North Korea.