Audio Transcript:

LISA MULLINS: I'm Lisa Mullins and this is The World. The US continues to warn that al-Qaeda may be planning to attack targets in Europe. The warning seems to be based largely on intelligence about a German-based group of militants. But while Islamist extremists may be plotting something, Western governments are working to foil them. Yesterday, a US missile strike in Pakistan killed eight militants, including four suspected German nationals. And today, French police detained 12 people, suspected of links to Islamist extremism. The BBC's defense and security correspondent Nick Childs is in London. This is a rather bewildering array of news here. Can you connect the dots for us? Are all these strands linked?

NICK CHILDS: There are certainly a lot of dots out there, Lisa. Quite how strong the links are between them I think is still not entirely clear. There certainly has been a general increase and concern about terror threats focused on Europe. Clearly as you were suggesting a lot of this has been due to intelligence from German sources about German-centered groups operating, or at least having had training, in the tribal areas of Pakistan. There's not doubt that the United States has been intensifying its drone strikes in the tribal areas because of mounting concerns about militant activity there. But there are also, as well as these very specific intelligence concerns, general worries that other European countries have about the increased threat. And that may be what we see with the French arrests for example. Whether the link is precise there is not certain, but there are at least elements suggesting that it might be worth looking at. For example, if we are talking about a coordinated attack along the lines of the Mumbai attacks, then what you need is things like organization and things like weaponry, and the arrests in France are allegedly linked to people who may have been involved with providing documentation for militants returning from Afghanistan and those involved in, perhaps, at least according to the French authorities, arms trafficking as well. So, some reason to look at that, too.

MULLINS: One of the things that seemed so surprising is the scale of this. I mean the numbers that we're hearing about. German authorities monitoring 100 suspected militants or more, possibly as many as 400 including a lot of battle-hardened veterans who have been fighting in Afghanistan. Is the scale comparable in France and Britain so far as we know?

CHILDS: I think there is concern that it is significant numbers that we're talking about. Whether in terms of specific impending threats, we're talking about quite so many people or whether there is a focus on perhaps smaller groups that may be a particular concern at the moment. I think we may be talking about rather smaller numbers in terms of the specific issues around the moment. But the problem is trying to keep track of all these groups and also knowing when the critical moment is when one needs to be particularly worried. For example, when they're in the tribal areas as they're alleged to be, they are a concern, but they are still, if you like, at arms length. It's when they start returning to their adopted countries or their countries of domicile at least, then keeping track of them, keeping an eye on what is going on, becomes even more critical.

MULLINS: Nick, there were explosives and firearms and forged papers that have been seized in France. There was an explosive device in Italy last week. What do we know right now about how close this plot or these plots were to fruition and what the actual targets are or were?

CHILDS: At the moment the signals are that this was a level of chatter that was raising issues of concern and a level of intelligence that was suggesting that things were forming up. But the impression one is getting from intelligence sources, particularly in Europe, is that this was not an imminent threat. It was something that was raising issues of concern, but it hadn't moved to the actual operationalization of it yet. That at least is the intelligence, but of course, one of the huge issues and judgments that has to be made by intelligence authorities. How good is there information? How long can you leave an operation or suspected operation in play in order to get the evidence you need to round up all the people that you think are a threat. And that is one area where although different governments say they are cooperating much more and those of a much higher level of cooperation, you have differences of view on when to go public, when to take action. Certainly between the United States, for example, and some European countries and maybe we've seen that playing out in the last few days and weeks with how this whole situation has become public.

MULLINS: Alright, thank you very much. The BBC's defense and security correspondent Nick Childs in London bringing us up to date on the alleged al-Qaeda to attack European cities. Thanks a lot, Nick.

CHILDS: Thanks, Lisa.