Agencies around the world treat this very differently.
If the committee were to release a report about the threat level, I think it would have to be with the co-operation of the intelligence agencies involved, because they're the ones who will appreciate the extent to which risk is created by revealing the threat level. Or, on the other hand, you may be content to reveal the threat level.
That's something you would take your counsel on from the agencies involved, which are closer to that. I don't think there's one answer to that question all the time.