(CNN) Construction began last week on the first new miles of barrier along the US-Mexico border since President Donald Trump took office, according to two Customs and Border Patrol officials familiar with the project.
Unlike previous construction under the Trump administration, this is the installation of a barrier where none existed before.
Customs and Border Protection, along with the Army Corps of Engineers, began installing panels for the new border wall in the Rio Grande Valley region of Texas last week, according to the agency.
The first panel was installed last Wednesday in Donna, Texas, said one of the officials.
Construction of the 30-foot-tall barrier is taking place in the Rio Grande Valley south of Donna, according to the other Customs and Border Protection official. The barrier in this region is a combination of levee wall and bollard fencing affixed on top.
The Rio Grande Valley is one of the busiest regions along the border, with 40% of all apprehensions occurring there.
Around 3 miles of wall are expected to be constructed over the next few months, said the second official. The contract for this project, which will use funds appropriated from Congress, was awarded a year ago and construction was initially scheduled to begin last February.
At the end of September, the total length of primary barrier along the Southwest border was about 654 miles. With the new wall going up in Texas, "the number of miles along the border changed," said the second official.
Last month, acting Customs and Border Protection Commissioner Mark Morgan touted the agency's wall construction in an interview on Fox Business.
"You're going to start seeing an increase of the miles of wall being built every week, and by the end of 2020, you're going to see 450 miles of new wall in strategic locations, mission-critical spots, built by the end of 2020," Morgan said.
At the end of September, Customs and Border Protection said it had constructed 69 miles of "new border wall system" in place of "dilapidated and outdated designs," according to the agency's data.
Despite the President's push to strengthen current border barriers and to build a wall along the southern border, law enforcement officials involved in day-to-day security near the border told CNN that cartels that profit from human smuggling continue to seek creative ways to bypass America's defenses.
Since the administration began erecting portions of bollard fencing along the southern border, Mexican gangs have sought to identify potential weaknesses in new and existing infrastructure.
"Whether it's newly-constructed barriers, or less advanced legacy systems, cartels are working to defeat them," said the official.
The agency plans to use about $9.8 billion, including appropriated funds and Defense Department money, on the construction of 509 total miles, a combination of replacement barrier and new miles.
As of September, Defense Department funds had been used to complete approximately one mile of replacement barrier in multiple locations, according to CBP.
In October, a federal judge in Texas ruled that Trump's national emergency declaration to build a border wall is unlawful and appeared poised to block the use of those funds.
The lawsuit -- brought by El Paso County, Texas, and Border Network for Human Rights -- seeks an injunction to block Trump's national emergency declaration. It argues that Trump overstepped his authority when he issued the declaration to gain access to additional funds for his border wall, despite receiving $1.375 billion from Congress.