Washington, January 26 (RHC)-- U.S. President Donald Trump has signed a directive to begin the construction of a wall on the border with Mexico, taking the first step to deliver on one of his most divisive campaign pledges. 

"We've been talking about this right from the beginning," the Republican president said as he signed the order during a ceremony for Homeland Security Secretary on Wednesday.  Reports say that the wall will be stretched across the roughly 2,000-mile (3,200-kilometer) U.S.-Mexico border. 

Earlier, Trump said during an interview with ABC News that the construction was slated to begin within months, while planning would start immediately.  Trump also asserted that Mexico would reimburse "100 percent" of the wall's costs. 

The U.S. president took another step aimed at curbing immigration by signing a separate executive action on public safety for the interior of the U.S., authorizing a crackdown on U.S. cities that shield illegal immigrants.  The directive aims to strip federal funding from "sanctuary" states and cities that harbor illegal immigrants. 

During his campaign run, Trump repeatedly pledged to build a wall along the southern border to prevent more immigrants from entering the U.S. illegally.  The Manhattan billionaire even estimated that erecting the wall would cost $8 billion, pledging to force Mexico to cover it. 

Earlier this month, however, Trump joined other Republicans, saying U.S. taxpayers may foot the initial bill for the proposed wall, insisting that Mexico would repay the U.S. the money in the end.