Grinning broadly, North Korean leader Kim Jong Un delighted in the global furor created by his nation's first launch of an intercontinental ballistic missile, vowing Wednesday to never abandon nuclear weapons and to keep sending Washington more "gift packages" of missile and atomic tests.

U.S. and South Korean forces, in response to Tuesday's launch, engineered a show of force for Pyongyang, with soldiers from the allies firing "deep strike" precision missiles into South Korean territorial waters. South Korean President Moon Jae-in ordered the drills arranged with the United States to show "North Korea our firm combined missile response posture," his office said.

A North Korean test of an ICBM, confirmed later by U.S. and South Korean officials, is a momentous step forward for Pyongyang as it works to build an arsenal of long-range nuclear-armed missiles that can hit anywhere in the United States. The North isn't there yet — some analysts suggest it will take several more years to perfect such an arsenal, and many more tests — but a successful launch of an ICBM has long been seen as a red line, after which it would only be a matter of time — if the country isn't stopped.

Worry spread in Washington and at the United Nations, where the United States, Japan and South Korea requested a U.N. Security Council emergency session, to be held later Wednesday. U.S. Secretary of State Rex Tillerson said the U.S. response would include "stronger measures to hold the DPRK accountable," using an acronym for the nation's formal name, the Democratic People's Republic of Korea.

The uproar only seemed to inspire the North, whose propaganda machine rarely fails to aggrandize its leader and its military or to thumb its nose at rivals Seoul and Washington.

A report in its state media Wednesday described leader Kim as "feasting his eyes" on the ICBM, which was said to be capable of carrying a large nuclear warhead, before its launch. "With a broad smile on his face," Kim urged his scientists to "frequently send big and small 'gift packages' to the Yankees," an apparent reference to continuing the stream of nuclear and missile tests Kim has ordered since taking power in late 2011.

The North was also pleased that its test came as Americans celebrated Independence Day. Kim, the state media report said, told "scientists and technicians that the U.S. would be displeased to witness the DPRK's strategic option as it was given a 'package of gifts' incurring its disfavor by the DPRK on its 'Independence Day.'" The North has a history of conducting weapons test on or around July 4.

Kim reportedly "stressed that the protracted showdown with the U.S. imperialists has reached its final phase and it is the time for the DPRK to demonstrate its mettle to the U.S., which is testing its will in defiance of its warning."

The test, North Korea's most successful yet, is a direct rebuke to President Donald Trump's earlier declaration that such a test "won't happen!"

A U.S. scientist analyzing the height and distance of the launch said the missile could potentially reach Alaska.

North Korea's Academy of Defense Science, in a bit of hyperbole, said the test of what it called the Hwasong-14 marked the "final step" in creating a "confident and powerful nuclear state that can strike anywhere on Earth."

South Korea's Defense Ministry, in a report to lawmakers, tentatively concluded that North Korea test-fired a "new missile with an ICBM-class range" of more than 5,500 kilometers. But the ministry said it's not certain if the test was successful because Seoul couldn't verify if the North has mastered re-entry technology for an ICBM. The ministry said North Korea may now conduct a nuclear test with "boosted explosive power" to show off a warhead to be mounted on a missile.

The launch sends a political warning to Washington and its chief Asian allies, Seoul and Tokyo, while also allowing North Korean scientists a chance to perfect their still-incomplete nuclear missile program. It came days after the first face-to-face meeting between Trump and Moon and ahead of a summit of the world's richest economies.

Hamish de Bretton-Gordon, a former commanding officer of the British Armed Forces Joint Chemical Biological Radiological Nuclear Regiment, said that "in capability of missile terms and delivery, it is a major step up and they seem to be making progress week-on-week." He added, however, that "actually marrying the warhead to the missile is probably the biggest challenge, which they appear not to have progressed on."

North Korea has a reliable arsenal of shorter-range missiles and is thought to have a small number of atomic bombs, but is still trying to perfect its longer-range missiles. Some outside civilian experts believe the North has the technology to mount warheads on shorter-range Rodong and Scud missiles that can strike South Korea and Japan, two key U.S. allies where about 80,000 American troops are stationed. But it's unclear if it has mastered the technology needed to build an atomic bomb that can fit on a long-range missile.

Soon after the launch, Trump responded on Twitter: "North Korea has just launched another missile. Does this guy have anything better to do with his life? Hard to believe that South Korea and Japan will put up with this much longer. Perhaps China will put a heavy move on North Korea and end this nonsense once and for all!"

"This guy" presumably refers to Kim. China is North Korea's economic lifeline and only major ally, and the Trump administration is pushing Beijing to do more to push the North toward disarmament.

After North Korea claimed earlier this year it was close to an ICBM test launch, Trump took to Twitter and said, "It won't happen!"

North Korea says it needs nuclear weapons and powerful missiles to cope with what it calls rising U.S. military threats.

Regional disarmament talks on North Korea's nuclear program have been deadlocked since 2009, when the North pulled out of the negotiations to protest international condemnation over a long-range rocket launch.

The missile test could invite a new round of international sanctions, but North Korea is already one of the most sanctioned countries on Earth.

Last year, North Korea conducted its fourth and fifth atomic bomb tests and claimed a series of technical breakthroughs in its efforts to develop long-range nuclear missiles. The fifth nuclear test in September was the North's most powerful atomic detonation to date.

The Korean Peninsula has been divided since the end of World War II. Almost 30,000 U.S. troops are stationed in South Korea.