North Korea has tested a new "tactical guided projectile" with a solid-fuel engine, state media said Friday after the nuclear-armed country carried out its first substantive provocation since US President Joe Biden's inauguration.
Pyongyang has a long history of using weapons tests to ramp up tensions, in a carefully calibrated process to try to forward its objectives.
Biden told reporters that UN resolution 1718 "was violated by those particular missiles that were tested".
Pyongyang had been biding its time since the new administration took office, not even officially acknowledging its existence until last week.
The US was "consulting with our partners and allies", Biden said Thursday, warning North Korea that "there will be responses if they choose to escalate. We will respond accordingly."
"I'm also prepared for some form of diplomacy, but it has to be conditioned upon the end result of denuclearisation," he added.
The firing was supervised by senior official Ri Pyong Chol, the official KCNA news agency reported, rather than leader Kim Jong Un.
It was successful with the two projectiles accurately hitting a target 600 kilometres (370 miles) into the Sea of Japan, known as the East Sea in Korea, it added—further than the 450 kilometres reported by South Korea's military.
KCNA said the weapon could carry a payload of 2.5 tons, in a dispatch that avoided using the words "missile" or "ballistic".
The test had confirmed the reliability of an improved solid fuel engine, KCNA added.
Pictures in Pyongyang's official Rodong Sinmun newspaper showed grinning officers applauding after the launch from a vehicle, most of them not wearing masks.
Vipin Narang of MIT said it appeared to be a weapon that the North displayed at a military parade in January.
"A 2.5 ton warhead likely settles the question whether this KN23 variant is nuclear capable. It is," he tweeted.
The test was "of great significance in bolstering up the military power of the country", KCNA cited Ri as saying, "and deterring all sorts of military threats existing on the Korean Peninsula".
The US stations 28,500 troops in the South to defend it against its neighbour, which invaded in 1950, while Pyongyang says it needs nuclear weapons to deter a possible US invasion.
At Washington's request, the UN North Korea sanctions committee will meet Friday morning behind closed doors, according to diplomatic sources, although no public statement is expected.
Pyongyang has made rapid progress in its capabilities under North Korean leader Kim Jong Un, testing missiles capable of reaching the entire continental United States as tensions mounted in 2017.
Ex-US president Donald Trump's first year in office was marked by a series of escalating launches, accompanied by a war of words between him and Kim.
The two then embarked on an extraordinary diplomatic bromance, holding two headline-grabbing summits in Singapore and Vietnam.
The United States pulled back on some joint military exercises with South Korea while the North froze intercontinental ballistic missile tests.
But the February 2019 Hanoi summit broke up over sanctions relief and what North Korea would be willing to give up in return.
Communications then dried up, despite a third encounter in the Demilitarized Zone that divides the Korean peninsula, and no substantive progress was made towards denuclearization.
Pyongyang carried out a series of weapons tests last year that it called "long-range artillery" but others described as short-range ballistic missiles.
Trump "had been willing to turn a blind eye to North Korea's ballistic missile launches as long as they were not tests of long-range missiles", said Jean Lee of the Wilson Center in Washington.
"But I suspect the Biden Administration will confront any confirmed ballistic missile launches that violate UN Security Council resolutions."
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Thursday's launch, and an earlier test of short-range, non-ballistic missiles at the weekend, came after joint exercises by the US and South Korean militaries and a visit to the region by US Secretary of State Antony Blinken and Defense Secretary Lloyd Austin.
During their trip to Seoul and Tokyo, Blinken repeatedly stressed the importance of denuclearizing North Korea.
Biden administration officials say they have sought to reach out to Pyongyang through several channels but have received no response so far.