The "speculation" of the use of a nuke came from an Arab source who don't have a clue about cause and effect in nuclear explosions and assume equal ignorance among their readers / viewers.
Congressman Billybob
Yes, I did say it was very unlikely. No doubt the EU, the Russians, and others have technical means to detect such an event. I doubt that Bush would risk the political firestorm that would accompany use of a nuke, even a tactical one, unless it were the gravest of circumstances.