The Department of Homeland Security announced Tuesday it has issued a waiver to expedite the construction of barriers at certain areas of the U.S.-Mexico border.

DHS said it waived "certain laws, regulations and other legal requirements to ensure the expeditious construction of barriers" at the international border near Calexico, California.

According to DHS, the waiver dealt with environmental, natural resource and land management laws.

The border infrastructure projects would be in the U.S. Border Patrols' El Centro Sector in California, an area where more than 19,400 illegal immigrants were arrested and thousands of pounds of marijuana and cocaine were seized in the last fiscal year. According to DHS, the waiver will help the Trump administration protect the border by starting work on a wall in that area.

"The department […] continues to take steps to immediately plan, design and construct a physical wall along the southern border, using appropriate materials and technology to most effectively achieve complete operational control of the southern border," DHS said.

In late August, DHS said four vendors would head to a site in San Diego in the coming weeks to begin construction on a variety of concrete prototypes that could become the model for the border wall.

"These prototypes will help us refine the design standards and security requirements that will meet the needs of U.S. Border Protection," U.S. Border Patrol Chief Ronald Vitiello told reporters during a presentation.

The four vendors who received contracts are based in Arizona, Texas, Alabama, and Mississippi. That announcement came nearly a month after DHS issued its first waiver to bypass environmental laws and regulations that could have prevented vendors from doing work in southern California.

One of Trump's biggest campaign promises was building a wall along the U.S. border with Mexico to prevent illegal immigration and the flow of drugs.