What We Know About North Korea's Nuclear Arsenal

North Korea soldiers
North Korean soldiers march as they visit a newly constructed residential complex after its opening ceremony in Ryomyong street. REUTERS/Damir Sagolj

Updated | On April 16 two enormous intercontinental ballistic missiles rolled through the streets of Pyongyang as part of Kim Il Sung's birthday celebrations. Kim, the grandfather of current North Korean ruler Kim Jong-un, has been dead since 1994 but the day he was born remains a national holiday.

It was an ominous time for a show of military strength. Just days earlier, U.S. President Donald Trump said he was sending an "armada" to the Korean Peninsula. It has since transpired the ships, which included aircraft carrier Carl Vinson, were moving further away from Korea, and into the western Pacific. This week Vice President Mike Pence has also visited the demilitarized zone that has separated North and South since the end of the Korean war in 1953.

In the corridors of power in Washington and Seoul, Pyongyang and Beijing, war is very much on everyone's minds. North Korea said Tuesday that a thermonuclear conflict may break out at any moment and in the last year the nation has carried out five missile tests, two of which it claims involved nuclear weapons.

North Korea's long-term ally, China, warned that "a storm is about to break" after Trump sent his "armada" to the Korean Peninsula, while Kim In Ryong, North Korea's deputy U.N. ambassador has accused the United States of turning the region into a "hotspot."

On Sunday morning, North Korea launched a ballistic missile that failed just as Pence was flying to Seoul and a senior official told the BBC that the country will test missiles on a "weekly, monthly, yearly" basis.

But how extensive is North Korea's weapons arsenal, and could it really attack the U.S. if it wanted to?

What missiles does North Korea have?

North Korea has carried out five missile tests in the last year and is in possession of four different types of missile. Its short range 'Scud' missile has a range of 500 miles , meaning it could reach Japan. Its medium range 'Nodong' missile is capable of hitting targets either in China or Southeast Asia. The 'Musadan' has a 2,500 mile range and could reach India while its 'Taepodong' missile has a 5,000 milereach and could target Scotland, Alaska, and Canada.

In terms of development, North Korea purchased its first missiles — Scuds —from Egypt during the 1970s but soon after began developing its own short range weapons known as 'Hwasongs'. Its longer range missiles have been developed domestically.

North Korea military parade
A North Korean navy truck carries the 'Pukkuksong' submarine-launched ballistic missile (SLBM) during a military parade marking the 105th birth anniversary of the country's founding father, Kim Il Sung, in Pyongyang, April 15. Damir Sagolj/Reuters

Where are its launch sites?

Different missiles require different sites: Punggye-ri is the main nuclear test site in North Korea's North East, although Youngdoktong, in the east of the country on China's border, could possibly be capable of an advanced weapons launch. Sangnam Ri, Yong-jo ri, Musadan Ri, and Sangnam Ri, are where ballistic missiles are launched from, and are all in the far north east, where the main concentration camps are located.

But a noticeable feature of the intercontinental ballistic missiles (ICBMs) that rolled through Pyongyang was that they were carried on tracks, enabling them to be carried off-road. This could make launch pads harder to detect.

The new ICBMs use solid, rather than liquid fuel, which means they can remain fueled, so can be fired at short notice, the New York Times reported.

How much do we know about North Korea's military?

It's impossible to know how many missiles North Korea has but experts estimate between 20 and 120 in total.

The Washington-based U.S.-Korea Institute stated in a 2016 report that: "The country is now estimated to possess enough fissile material to build anywhere from six to about 30 nuclear weapons, depending largely on how much highly enriched uranium it has produced, and is poised to grow its stockpile, perhaps dramatically, over the coming years."

In 2015, China predicted that North Korea had just 20 missiles, while the U.S. Congressional estimate is that North Korea has between six-10 nuclear weapons, the Wall Street Journal reported.

A BBC article published in February estimated that North Korea has 1,000 weapons stockpiled, including long-range missiles.

How big is North Korea's army?

North Korea has more than 1.2 million soldiers, and 7.7 million in reserve which makes its ground force one of the largest in the world.

It has Song-Un, or a "military first" approach to the population, which means prioritizing the military when it comes to allocating resources. As a result, children are indoctrinated from a young age and school books regularly show guns firing and tanks killing Americans.

According to The Military Balance report, an annual assessment of global military, conducted by the Institute for International Studies, North Korea is in possession of 3,500 tanks, 72 submarines, 302 helicopters, and 563 combat helicopters, although apparently most of those were grounded for maintenance at some point during the last year.

Does it have nuclear weapons?

In 2016, North Korea said it had carried out two nuclear tests, in January, and in September.

Cristina Varriale, an expert in North Korea from RUSI, the Royal United Services Institute, tells Newsweek : "The January test was nuclear, but North Korea claim it was thermonuclear—a H-bomb and it probably wasn't that, just a standard atomic bomb."

To launch a nuclear attack, North Korea needs to be able to make a nuclear warhead small enough to fit into a missile, and so far, it's been unable to do so. Pyongyang has claimed it has "miniaturised" the warhead but there is doubt over this. "North Korea likes to exaggerate its successes," says Varriale.

Last year, North Korea said it was in possession of a hydrogen bomb, that could "wipe out the whole of the U.S. at once," but experts have been unable to verify this.

What will happen next?

Pence, who is currently on a 10-day tour around South Asia, reiterated America's support for Japan on Wednesday. "The U.S will counter any attack with an overwhelming response," he said to an audience of Japanese and American military.

North Korea is unpredictable, which is what makes it a force to be reckoned with, but China, its longstanding ally, is ramping up the pressure on Pyongyang to resolve tensions diplomatically and end the standoff. And China isn't alone in hoping that the increasingly hostile language from North Korea—as well as the U.S.—won't translate into actual conflict on the Korean Peninsula.

This article has been updated with a different quote from Cristina Varriale​.