Strange behavior by American government agencies. Should we be worried?

I'm not American and I don't know your procedures in detail. However, I do know that whenever something alarming enough happens, various authorities rush to deny it, usually with a press conference, or at least to reassure public opinion.

But now, after growing alarmism about national security due to the overflights of the infamous "drones" over sensitive areas and the strong accusations coming from authoritative figures against the main agencies involved in civil and military defense, has no one yet rushed to deny it? Can any US citizen explain to me how to interpret this attitude? Is it a prelude to other events, or is each government agency simply hiding behind its own hole? Thanks to anyone who can explain.