Here follows a transcript of the interview, made by P4 Extra's Lotta Bromé.
How serious is the situation?
It has been serious for several years. More than one hundred thousand people have been killed in the civil war which has become much worse. What happened between Tuesday and Wednesday last week is an attack clearly with deathly chemical substances used by the regime's forces. We have all seen the pictures and abhor it. Now we are discussing what needs to happen.
Do you share the American view that it is the government forces who have carried out this attack?
I said already a few days ago that I was convinced this is an attack from the regime forces and that it has consisted of chemicals that are lethal. I cannot know exactly who has ordered it, and I cannot know exact which substances it was. And that is why the UN-inspectors are so important, they are now there to make tests and interview people and I hope they can return to New York in the next few days, to start reporting to the UN security council, that is where the crucial discussions will have to take place.
Is it a problem that several leaders express views about the culprit before it is known for sure?
Not necessarily. I have also expressed my view based on the information available. And there has to be a reaction from the International Community and UN security council, that is self-evident. We cannot just sit silent and watch these things happen. But it is also important that we wait for the report from the UN inspectors.
The UK, France, Denmark, Turkey and others have said that they would support the US in a possible military action. What does this mean?
We are not there yet. Lets wait for the discussion in the UN security council. What the UK has done today is that they have come with a proposal for a UN resolution. I think that is good. I have welcomed it. They will show it this afternoon to the five permanent members (of the security council) and there are well known differences of opinion there. But of course there has to be a discussion in the Security Council as a whole about this, and I think they will be very clear that they want to wait to hear what the UN inspectors have to say. They may not be able to answer all the questions, but they will be able to give a clear and precise answer to the questions where they are able to answer.
Has Sweden been asked to contribute to a possible military action in Syria?
No we have not and I don't really expect it either. I think that if there will be something like that, it will be a relatively limited affair which will happen quickly and with contributions in terms of weapons and capacities that we do not have in Sweden. But in the last few days I have had many and ongoing talks with my Nordic and European colleagues about how we see this and what we can do about it.
What are they saying?
It is pretty unanimous judgement. Abhorrence of what has happened, concern about the situation and a wish that nothing happens which will make a political solution more difficult. A political solution is the only sustainable way to stop the killing and the misery and the destruction in Syria and in the region as a whole. There is a lot of focus on whether we can use the fact that all these awful things are happening to turn it into support for a political process, to get everybody to the negotiating table, to get the Russians and the Americans to speak a bit more constructively with each other. If this is possible or not we do not know, but we have a responsibility to try.
The UK Foreign Minister William Hague cancelled his visit here, and now many wonder with me if president Obama may cancel his visit to Sweden next week also be cancelled?
I do not know anything about it, I have no reason to believe so. And that has partly to do with a bit bigger things. There is a G20 meeting in St Petersburg on the other side of the Baltic, to discuss the global economy. It would be very unfortunate if that meeting would be cancelled and I have no reason for this not to happen. G20 is important whatever happens and it is hard to see that this summit would not happen in the shadow of things in Syria. The use of lethal chemical substances does mean a completely new situation, and no-one can be indifferent to that, not in St Petersburg either.