From what they have achieved so far, these beings are definitely not mere creatures. They are highly intelligent, possibly highly evolved or at least more technologically advanced than we are since traveling to another world is a quite a feat. For all we know, they might have been here a long time ago.
The authorities most likely know something but most are still unsure if these invaders are peaceful. They could be the ones manipulating the government with the cover-ups and all. They could also be planning something on a grander scale. Go public officially perhaps, or a hostile takeover that could endanger the human species' existence.
How would our weapons fare with theirs then? Let's just say, they didn't come all the way here by accident and we have to assume that they have been preparing. There may or may not be just one race that threatens us and treachery could play a key role to our downfall. They could just cut the power off every fighter planes or rockets we have if they're that smart. With that in mind, we're already as good as extinct. Of course I'm still hoping that I'm wrong to have underestimated power of the human race.
Below is a video I found on Youtube: a media coverage compilation regarding UFOs appearing to the public. An eerie call to a radio show that talks about the things to come is in there too. It was later dismissed by the very caller and apologized to the host about the prank he pulled earlier. Real or not, it still doesn't explain the sudden interruption that cut the call.