Trump orders US-Mexico wall construction, tighter illegal immigration policies

President Donald Trump signed an executive order Wednesday to begin construction of the famous wall along the Mexican border that was one of his key campaign promises.

The order states the administration will: construct a physical wall along the border, hire additional border patrol agents, create more detention space for illegal immigrants along the Mexican border, eliminate "catch-and-release" policies, and prioritize prosecution of criminal offenses.

Trump tweeted out last night that Wednesday would be a "big day for national security."

Multiple media reports also suggest he may outline other regulations to curb illegal immigration, such as targeting so-called sanctuary cities.

Officials say Trump also is reviewing proposals that would restrict the flow of refugees to the United States.

The Associated Press contributed to this report.