"Trump’s transition team did not comment in response to Reuters inquiries." 

Trump's team really want to build their walls to hide what is actually happening behind them.

More Mexicans have been leaving the US than coming  to the US for quite some time :

http://www.huffingtonpost.com/entry/immigration-reverse-more-mexicans-are-leaving-us-than-coming-in_us_564e04a4e4b031745cf02dfb