NEW YORK • Even as North Korea fired off a series of missiles in recent months - at least 18 since May - US President Donald Trump repeatedly dismissed their importance as short-range and "very standard" tests.
And although he has conceded "there may be a United Nations violation", he also said any concerns are overblown.
Mr Kim Jong Un, North Korea's leader, just "likes testing missiles", Mr Trump explained recently.
American intelligence officials and outside experts have now come to a far different conclusion: that the launches downplayed by Mr Trump, including two last month, have allowed Mr Kim to test missiles with greater range and manoeuvrability that could overwhelm US defences in the region.
Japan's Defence Minister Takeshi Iwaya last week said the irregular trajectories of the most recent tests were further evidence of a programme designed to defeat the defences Tokyo has deployed, with US technology, at sea and on shore.
Mr Kim's flattery of Mr Trump with beguiling letters and episodic meetings offering vague assurances of eventual nuclear disarmament, some outside experts say, are part of what they call a strategy of buying time to improve his arsenal despite sanctions on North Korea.
The rapid improvements in North Korea's short-range missiles not only put Japan and South Korea in more danger but also threaten at least eight US bases in those countries housing over 30,000 troops, according to an analysis of the missile ranges by The New York Times. Such missiles, experts say, could be designed to carry either conventional or nuclear warheads.
"Kim is exploiting loopholes in his agreements with Trump pretty brilliantly," said Dr Vipin Narang, a political science professor at MIT who studies North Korean weapon advances. "These are mobile-launched. They move fast, they fly very low and they are manoeuvrable. That's a nightmare for missile defence. It's only a matter of time before those technologies are migrated to longer-range missiles."
The recent bout of testing began in May when North Korea fired a 9m-tall missile from an eight-wheeled truck. Analysts say it was a solid-fuel rocket that can be launched in minutes - unlike liquid-fuelled missiles, which can take hours of preparation.
In all, the North conducted eight flight tests of the new missile in May, July and last month. Its maximum range was found to be roughly 692km, according to the Centre for Nonproliferation Studies, a private group in Monterey, California. The missile, if perfected, could target all of South Korea, including at least six US bases and parts of southern Japan, including two large bases.
North Korea debuted another type of missile in July and early last month, along with a new launching system. Mr Vann Van Diepen, a top official on weapons of mass destruction in the Office of the Director of National Intelligence until 2009, described the system in 38 North, a respected publication on North Korea, as a new generation of weapon that could fire an unknown number of missiles simultaneously.
The range of the newly tested missile, he wrote, was 240km, about 64km farther than the older version. Mr Van Diepen said it would increase the North's ability to subject US and South Korean targets to "saturation attacks", which can also defeat anti-missile defences.
North Korea tested a third new missile twice last month. It also fired two projectiles from what it called a "super-large multiple rocket launcher". Dr Narang said the system appeared new.
Stanford University lecturer Daniel Sneider, who has spent years in Asia studying the interplay of American and regional defences, said: "It is a mistake to see North Korean missile-testing as simply forms of political messaging.
"In every case, the North Koreans have very clear and specific military goals, systems that they want to demonstrate and test before they field them."