Before North Korea's announcement that it had tested a nuclear bomb "in the future", the BBC News website spoke to people in Japan and South Korea about their fears for regional security. We first spoke to the group after North Korea test fired missiles in July.
HISANO, SOCIAL SCIENTIST, KYOTO, JAPAN
Shuji Hisano is worried about Japan's reaction to the threats
I'm very worried and very fearful about the prospect of nuclear tests. In North Korea, the decision-makers are crazy when it comes to politics. But they are the government. They have the power.
So I believe there is a very serious threat to regional peace.
It seems to me that North Korea's policy is a reaction to the ascension of our new prime minister, Shinzo Abe.
People are not talking about it openly, but there is a great deal of worry behind the scenes. My concern is that the Japanese government will capitalise on the sentiments of the Japanese people and try to bolster our own military.
I don't deny that many Japanese people believe that North Korea is a major threat. This is especially the case, given our history with nuclear bombs.
But it is not good to focus on that sentiment without paying attention to the consequences our own policies.
The government wants to revise our constitution to allow us to build up our military. It is very dangerous for Japan to become militarised, especially with a militarised North Korea and China.
I see the potential for future conflict. I'm filled with suspicion at everybody's motives - and not just North Korea.
KIM JI-HYE, STUDENT, PUSAN, SOUTH KOREA
Kim Ji-hye believes the nuclear tests may not happen
After the missile tests of the summer, I was a little scared of what the future might hold. But North Korea test-fired the missiles and nothing happened.
I can't count how many times they have threatened something and not carried it out. They have also said many times that they would not harm South Korea.
So, I'm not sure this test will really happen.
I think most Koreans are not afraid anymore. Because, if the test happens, it will be just a test. It will not be real military action.
People are sick of North Korea's actions, many say they do not care.
I feel that North Korea has totally isolated itself and we should have a more hardline policy against the state. All our attempts at friendship have had no effect.
I'm not saying that we should take the line of the US. We should certainly make our own decisions, but we cannot ignore the mode of thinking that says we must be harsh.
It's difficult because I still feel the same sympathy for the North Korean people but the government makes me really angry.
SHIROKI NEGISHI, 38, ENGINEER, TOKYO, JAPAN
Shiroki Negishi believes the timing of these tests is deliberate
When I first heard the announcement, I thought it was just sabre-rattling.
The North Korean government is getting more desperate because we have cut its access to funds. It aims to get that money flow going again. That is not going to happen.
I think the timing of these threats is very interesting.
Our new prime minister is visiting China and South Korea. Strained relations between all of these countries was on the agenda before. Now, the top issue on the agenda is very clear.
The consensus in Japan is that this dangerous regime has to go.
There is real fear. It's like seeing somebody waving a gun about wildly. You are stunned by the fear but there is not much you can do about it as an ordinary citizen.
At the moment, it is only words. But if they actually conduct the tests, that could call for further action from regional neighbours.
We have to show them that we are not going to budge - they are the ones who are going to have to fold on this issue.
If they do conduct these tests, any element of sympathy here for the people and the country of North Korea will disappear.
KIM JIEUN, NURSE, 24, FROM SEOUL
Jieun Kim says S Korea must have courage to oppose the North
I find the news completely unbelievable. I don't understand what the North Korean government is doing.
I believe the heart of this matter is to do with the fact that many countries have stopped providing financial support to North Korea.
They are showing the world that they have power, they want to show the world how strong they are and how they have capability with nuclear weapons.
But if they conduct these tests, there will be serious consequences. I truly hope our government refuses to support North Korea in future.
But even when it knew North Korea was going to test missiles in the summer, the government sent rice and money over there.
No matter what happens, I feel that parts of our government supports that state.
There are people who feel that North Korea is like our family, they are Korean too after all. But it's not like that and nor should it be.
If we support them like this the situation will only get worse. It's not that I think we should never support North Korea. But we are a democratic society and we have to show that we do not agree with their politics and their way of thinking.
Our government has to show its strength.