If you look at this article with a squint - it seems to be a publicized threat from the US government to the Maduro regime, loosely veiled as an independent news article?
Daddy wants a fight to prove he's a man and make everyone admire and adore him like he deserves to be admired and adored, so he's picking on the guy everyone wants gone.
If you understand what is going on in terms of Trump's very personal, broken malignant psychology and his very literal tendency to agree with the last person who spoke to him, you can see very old-fashioned US business interests have persuaded him to gin up an old, old fight.
(Always interesting to think that Trump may be projecting his own faults onto Maduro; every accusation a confession)
The last time this happened, Hugo Chavez very nearly had a much shorter trip in a helicopter than was scheduled, and the US ambassador rushed down from the embassy uncomfortably too early to congratulate the new guy only to find that the new guy was still the old guy. Almost as if they were expecting something to happen that didn't.
(Don't read this as a suggestion that I think Maduro is legitimate; I don't.)
Leaks about a military buildup are only possible if there's an actual military buildup. Unless the leaks are false. Is there any indication the information is false?