North Korean leader Kim Jong Un, center, guides the test-firing of a new multiple launch rocket system in this undated photo released by North Korea’s Korean Central News Agency in Pyongyang on March 4, 2016. (KCNA/Via Reuters)

North Korea conducted its first nuclear test exactly 10 years ago Sunday, exploding a crude atomic bomb and crossing what had long been considered a “red line.”

A decade of condemnation, sanctions and ostracism later, the regime in Pyongyang has not pulled back. Far from it.

Today, the country has a demonstrated nuclear weapons program, has made clear progress with missiles and is widely assumed to be able to put the two together. The only real question now is whether North Korea can deliver a nuclear-tipped missile to a target, and that is not much of a question. If it cannot yet, it will soon, analysts say.

North Korea is “racing towards the nuclear finish line,” as Van Jackson, associate professor at the Asia-Pacific Center for Security Studies, a Pentagon think tank in Hawaii, puts it.

The next demonstration of leader Kim Jong Un’s intent could come as soon as Monday.

Large screens show Korean rocket launches, missile tests, ground war footage as well as other patriotic imagery as the Korean People’s Army State Merited Chorus and Ensemble performs at a concert in Pyongyang on May 11, 2016. (Linda Davidson/The Washington Post)

Oct. 10 is the anniversary of the establishment of North Korea’s ruling Workers’ Party — an event celebrated with fanfare — and Pyongyang likes to time its provocations. Last month’s nuclear test was carried out on the country’s Foundation Day.

[North Korea conducts fifth nuclear test, claims it has made warheads with ‘higher strike power’]

As a bonus, presidential candidates Hillary Clinton and Donald Trump will be taking to the stage for their second debate on Monday morning, Korea time.

Preparations for another test could be underway. The latest commercial satellite imagery shows activity at all three tunnels leading into the nuclear test site at Punggye-ri, analyst Jack Liu wrote Thursday on 38 North, a website devoted to North Korea.

Even if North Korea lets Monday pass, there still may be fireworks before the year is out.

“That would make perfect sense in the warped logic of North Korea,” said Andrew Shearer, a former Australian national security adviser now at the Center for Strategic and International Studies in Washington.

Hong Yong-pyo, South Korea’s unification minister, told a parliamentary hearing two weeks ago that he expected another provocation — a nuclear test or another long-range-missile launch — before the end of the year.

North Korea has been pursuing nuclear weapons for decades, ramping up efforts after the collapse of its benefactor, the Soviet Union, and the end of the Cold War. But Kim Jong Il, the second-generation leader who ruled North Korea between 1994 and 2011, appeared to restrain the program because of Chinese pressure.

That is not the case with his son.

Kim Jong Un has ordered 49 missile tests in the almost five years since he took over, including 21 this year. He has also presided over three nuclear tests, two of them in 2016.

By contrast, North Korea conducted 26 missile tests and two nuclear tests in the 18 years that Kim Jong Il was leader.

[N. Korea inches closer to being able to send a nuclear-tipped missile to the U.S.]

“With the ballistic missile tests one after the other, they seem to be under tremendous pressure to advance their program,” said David Albright, president of the Institute for Science and International Security, a Washington think tank that focuses on nuclear weapons.

North Korean scientists did not even appear to be taking the time to drill back into the nuclear test site to analyze the Sept. 9 explosion, a standard step that gives scientists a lot of information. “It’s really troubling,” Albright said of the pace of missile and nuclear testing.

The speed of the testing is breathtaking, but analysts seem to be more worried that North Korea is learning a lot and making big technical advances.

When North Korea first claimed to have launched a ballistic missile from a submarine in May, there was much derision because it appeared that the photographs had been doctored. Fast forward to August, and North Korea carried out a successful test from a submarine.

“It seems like North Korea is trying to build a wide array of delivery platforms so that they’re able to hit Japan, South Korea, American assets in Asia, and eventually, the homeland,” said Vipin Narang, a political scientist and expert on nuclear proliferation at MIT.

As the international community tries to formulate a harsh response to last month’s nuclear test, Pyongyang is likely to continue to hone its technology, experts say.

The September test was North Korea’s largest yet, with an explosive yield equal to about 10 kilotons of TNT. But Albright said he expected that the country would now try to find ways to boost its bomb’s yield up to 20 or 25 kilotons. The atomic bomb that the United States dropped on Hiroshima in 1945 had a yield of about 15 kilotons.

[These North Korean missile launches are adding up to something very troubling]

The recent developments are alarming policymakers in neighboring countries and in the United States, leading to increasingly frequent talk about preemptive strikes — an option long considered so impossible it was hardly ever mentioned.

In the vice-presidential debate Tuesday, Democratic candidate Tim Kaine suggested he would support striking North Korea to stop a nuclear attack on the United States.

Mike Pence, his Republican rival, said that a President Trump would not allow North Korea to “flout American power.”

The South Korean Defense Ministry said this past week that it would consult with its American ally “over a possible preemptive strike against North Korea . . . in case of an imminent nuclear attack by the North.”

U.S. leaders have long ruled out taking military action against Pyongyang. This is partly because there is no appetite in the United States for another war, and partly because preemptive action would almost certainly lead to the devastation of Seoul, a city of 20 million that is within range of North Korea’s conventional artillery.

[Everything you need to know about the North Korean nuclear test]

But the advances in North Korea’s nuclear weapons program are starting to change the conversation in Washington, where the words “preemptive strike” are more regularly mentioned. “We’re still a long way from seeing the U.S. moving in that direction, but there has been a noticeable change in the dynamic,” Shearer said.

Meanwhile, some analysts are concerned about an accidental escalation, perhaps during joint exercises between the U.S. and South Korean militaries, or that North Korea might make its own preemptive move.

With its relatively small nuclear arsenal, North Korea might judge that its best strategy is to go first, Jackson said.

“If they have small numbers of nukes and they see the cavalry coming, their options are to sit on them and lose them, or use them and hope that it achieves something,” he said.

Narang said North Korea no longer appears to be following the Cold War model of having nuclear weapons for mutually assured destruction but seems to be looking more and more like Pakistan, which has adopted a strategy of “asymmetric escalation” — being able to use a nuclear arsenal against a conventional attack.

“It looks like North Korea is thinking about what it would look like if they had to use these weapons on their own,” Narang said. “This program is no longer a joke.”

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Today’s coverage from Post correspondents around the world