Apparently the Pentagon has rebuffed the allegation:Not a military base, but this is going to alarm a lot of people if true
archived version
There are also fishy things going on inside the article itself (apart from WSJ being an absolute ret4rd whenever it comes to China reporting):
In a rare alignment of stance with the Pentagon, Havana too has officially rebuked the allegation.
It is said that the White House also disagreed with the allegation.