Jan. 25 (UPI) -- One of the most talked-about and controversial promises of President Donald Trump's campaign took one official step closer to becoming reality on Wednesday.
During a visit to the Department of Homeland Security, the president signed an executive action directing federal agencies to prepare for construction of a "large physical barrier on the southern border."
Trump said work on the wall will begin within months.
"We are in the middle of a crisis on our southern border," Trump said after signing the orders. "Beginning today, the United States of America gets back control of its borders -- gets back its borders."
"I just signed two executive orders that will save thousands of lives, millions of jobs and billions and billions of dollars," he added. "These two orders are part of an immigration reform we outlined during the campaign. I want to emphasize that we will be working in partnership with our friends in Mexico."
The wall is intended to shore up border security and keep migrants from unlawfully entering the United States. Trump has previously said the years-long flow of undocumented immigrants across the border has disrupted the American labor market and coincided with a rise in crime in southwest states.
"The secretary of homeland security, working with myself and my staff, will begin immediate construction of a border wall," Trump said. "This wall will also help Mexico by deterring illegal immigration from Central America and by disrupting violent cartel networks."
"We are going to get the bad ones out -- the criminals, the drug deals and gangs," he continued. "The day is over when they can stay in our country and wreak havoc."
During his campaign, Trump repeatedly said Mexico's government would pay for the wall -- a proposition Mexican President Enrique Peña Nieto has flatly rejected. Trump acknowledged Wednesday that the wall would be funded initially by American taxpayers -- but said Mexico City would reimburse the cost "100 percent" at a later date.
Nieto is scheduled to visit the White House next week.
"I have a deep admiration for the people of Mexico," Trump said, noting that the partnership will work to dismantle drug cartels and stem the flow of illegal weapons and money from the United States into Mexico. "They have to stop it, we have to stop it."
"Building a barrier is more than just a campaign promise, it's common sense, the first step to really securing our porous border," White House spokesman Sean Spicer said earlier.
Trump also signed a second immigration-related executive action on Wednesday, which strips so-called "sanctuary cities" of their federal grant money and allows for the construction of more detention centers. The president said it ends the "policy of catch and release" at the border and requires other countries to take back their criminals.
"They will take them back," Trump said.
The second order also establishes new support for victims of "illegal immigrant crime," he said.
"To all of those hurting out there, I repeat to you these words -- we hear you, we see you and you will never, ever be ignored again."
The cost of a wall on the border has been estimated at $20 billion by construction experts.