SEOUL — North Korea on Monday boasted of a successful weekend launch of a new type of ‘‘medium long-range’’ ballistic rocket that can carry a heavy nuclear warhead.
Outsiders also saw a significant technological jump, with the test-fire apparently flying higher and for a longer time period than any other such previous missile.
Amid condemnation in Seoul, Tokyo, Washington, and Moscow, a jubilant North Korean leader Kim Jong Un promised more nuclear and missile tests and warned that his country’s weapons could strike the US mainland and Pacific holdings.
North Korean propaganda must be considered with wariness — Pyongyang has threatened for decades to reduce Seoul to a ‘‘sea of fire,’’ for instance — but Monday’s claim, if confirmed, would mark another big advance toward the North’s goal of fielding a nuclear-tipped missile capable of reaching the US mainland.
Some experts, including officials in Tokyo, estimate that Sunday’s launch successfully tested a new type of missile, potentially the longest in North Korea’s arsenal.
The test is also an immediate challenge to South Korea’s new president, Moon Jae-in, a liberal elected last week who expressed a desire to reach out to North Korea.
Pyongyang’s aggressive push to boost its weapons program also makes it one of the Trump administration’s most urgent foreign policy worries, though Washington has struggled to settle on a policy.
Kim witnessed the latest missile test and ‘‘hugged officials in the field of rocket research, saying that they worked hard to achieve a great thing,’’ according to KCNA.
The rocket, ‘‘newly designed in a Korean-style,’’ flew 490 miles and reached a maximum altitude of 1,310 miles, the North said, and ‘‘verified the homing feature of the warhead under the worst reentry situation and accurate performance of detonation system.’’
South Korea’s Defense Ministry said more analysis is needed to verify the North’s claim on the rocket’s technological features. Spokesman Moon Sang Gyun said it’s still unlikely that North Korea has reentry technology, which would return a warhead safely back into the atmosphere.
Japanese officials said Sunday that the missile flew for half an hour and reached an unusually high altitude before landing in the Sea of Japan.
Several South Korean analysts, including Lee Illwoo, a Seoul-based commentator on military issues, said the missile flew higher and for a longer period than any other the North has ever test-fired.
North Korea is not thought to be able yet to make a nuclear warhead small enough to mount on a long-range missile, though some outside analysts think it can arm shorter-range missiles with warheads.
Each new nuclear and longer-range missile test is part of the North’s attempt to build a nuclear-tipped intercontinental ballistic missile.
Kim said North Korea would stage more nuclear and missile tests in order to perfect nuclear bombs needed to deal with US ‘‘nuclear blackmail.’’