I think it's an oblique threat. Just recently Trump made a direct threat on the bond markets.
https://www.mediaite.com/media/tv/trump-suggests-he-can-use-...
https://www.mediaite.com/media/tv/trump-suggests-he-can-use-...
I wish a reporter would ask him what question he heard and answered, because I'm sure he would be unable to correctly answer.
People are not quite sure, but Krugamn (for one) is willing to fight: