The Republican presidential contender also said he would rescind Obama's executive orders on immigration.
Some economists, activists and regulators predict that without stronger enforcement, the number of workers getting cheated out of a legal wage is bound to increase in places where wages rise.
Sneaking across the San Ysidro border crossing has become far more difficult, even for the most fit and fearless.
A focus on border security as a pre-condition of any overhaul of the nation's immigration laws has become a common policy point among many of the Republican candidates for president.
The U.S. found 181 tunnels in the border area.
Between 70 and 100 women were called into courtrooms at the Dilley campus last week and told by ICE officials that they could be released with ankle monitors in lieu of bond.
The Drug Enforcement Administration (DEA) included Joaquín "El Chapo" Guzmán in its list of major international fugitives.
Demographers at the University of Texas San Antonio and the University of New Hampshire say the number of immigrants coming from Mexico peaked in 2003, and has fallen by more than half since then.
"One of the reason you're seeing so many 2016 candidates go out of their way to smack Donald Trump is they don't like a politician that speaks directly about the challenges of illegal immigration," said Sen. Ted Cruz of Texas.
The authorities are ready to work with Mexico, expressed secretary of Justice Loretta Lynch.