The delivery systems a country possesses determine its ability to use its weapons - be it conventional, nuclear or biological - in the event of a war. The systems range from hi-tech options such as ballistic missiles, cruise missiles and combat aircraft to low-technology ways of using artillery and ground-based vehicles. Despite efforts to curb the spread of these systems, many countries around the world continue to acquire them.

And those already in possession of these technologies, such as North Korea, appear steadfast to improve and expand their arsenals. Pyongyang's nuclear program has been a key bone of contention the communist regime and the international community, particularly after the isolated East Asian nation conducted nuclear tests in 2006, 2009 and 2013.

While the country's current inventory is well-developed, the regime has "bigger ambitions and is seriously pursuing the deployment of more capable, longer-range, more survivable weapons," concludes a recently released report by 38 North, a program of the US-Korea Institute at the School of Advanced International Studies (SAIS) of Johns Hopkins University.

Titled "The Future of North Korean Nuclear Delivery Systems," the report dwells into North Korea's current missile program and offers various scenarios for the country's future nuclear delivery systems capabilities.

In a DW interview, Joel Wit, founder and editor of 38 North as well as the project lead, says that North Korea could be a significant threat to the region by 2020 even without any new missile and nuclear weapons tests. He stresses that international sanctions against North Korea have so far been totally unsuccessful in terms of stopping the country from importing nuclear technology.

DW: According to your findings, how would you assess North Korea's present nuclear arms capabilities?

Joel Wit: We estimate that North Korea possesses anywhere between 10-16 nuclear weapons, and that they are able to put these weapons on top of at least medium-range missiles, which are able to hit most targets in Japan and South Korea.

North Korea has a small nuclear arsenal, but the most important point we are trying to make in the report is that they could be on the verge of rapid expansion of both their nuclear arsenal and their delivery systems over the next five years.

What are the main findings of your report?

In terms of nuclear weapons, North Korea would have a stockpile of between 20 and 100 bombs by 2020, depending on several factors such as the amount of resources it pours into its nuclear program and the country's ability to acquire foreign technology.

But while North Korea has mastered nuclear weapons technology over the past 25 years, developing the delivery systems has proved to be more difficult and remains a significant engineering challenge.

For instance, if you look at North Korea's missile program, it is still mainly using old soviet technology. Nevertheless, it is important to note that the country has about 1,000 missiles that can reach targets in the region, and they require no new testing. The bottom line therefore is that North Korea could be a significant threat to the region by 2020 even without any new missile and nuclear weapons tests.

Who is supporting North Korea in developing its nuclear delivery systems capabilities?

Right now, we believe it's very much an indigenous program. There is no more foreign assistance for North Korea's old liquid-fueled rockets. However, what we find is that some of the newer systems that are appearing are also based on old Russian technology. And it's not quite clear whether North Koreans are able to produce them by themselves or they acquired a these technologies somehow from Russia in the past.

Although there is a bit of uncertainty, we think the North has the capabilities to take care of their main basic missiles - the liquid-fuel ones - in their arsenal.

What challenges does North Korea's nuclear program currently face?

One of the things we are not clear about North Korea's nuclear capabilities is the size of their program to produce highly-enriched uranium. We know it exists but we are not sure how advanced it is. So the issue is how many nuclear plants they have and how much uranium can they produce. And that's one of the factors that influence our projections.

In terms of the qualitative capabilities of their nuclear weapons, the main consideration is of course whether they can mount their weapons on top of missiles or not. Although there has recently been some talk about North Korea being able to put weapons on top of intercontinental missiles, we are skeptical about it and believe it requires more testing for the country to acquire that capability.

How successful have the current international sanctions been in curbing Pyongyang's nuclear activities?

The sanctions have been totally unsuccessful in terms of stopping North Korea from importing nuclear technology. I don't think they have had any impact on Pyongyang's ability to acquire more capabilities. North Koreans have been evading sanctions for decades, and on top of that I would say that the enforcement of these sanctions by the international community has been very lax.

What level of threat does the North's nuclear capability pose to the countries in the region?

If I was a South Korean or Japanese, I wouldn't want a North Korea that could be armed with a 100 nuclear weapons in the next five years. I would be very concerned about that development, particularly if the relationships in the region remain tense. It’s certainly not a good scenario and could get much worse.

What should the international community do to stop or at least slow down North Korea's pursuit to develop more advanced weapons and delivery systems?

The problem right now is that everything we are doing is currently not working. We have no diplomacy, and sanctions aren't working at all. I would even go further and say that the recognition of this growing threat is lagging behind the speed at which it is growing.

I think we really do need to have a reassessment of what's going on in North Korea, and based on that we need to find a new approach to tackle the issue. The approach is going to require thinking about serious sanctions; making them tougher and actually enforcing them. But it would also need thinking about serious diplomacy to identify peaceful paths to move forward.

Unfortunately, I don't believe any of that is going to happen. The US is pretty much done in terms of dealing with North Korea and is consumed with Iran, and I don't think that's going to change.

Joel Wit is the founder and editor of 38 North, a program of the US-Korea Institute at the School of Advanced International Studies at Johns Hopkins University.