"Before the wall, a common size group in this area was anywhere from 25 to even 40 at a time because the smugglers knew that there was nothing impeding their movements here, there was nothing that they had to scale like they do now," Rodriguez said. "The groups have gone down to maybe 12 or 15 at the most that we've seen in this area because of the wall… they know we have some technology here that's assisting us to detect the illegal activity so they know it's a lot more difficult for them to get past this area."
The Rio Grande Valley sector is responsible for securing 316-river miles of the US-Mexico border, but only has 55 miles of fencing. In addition to trafficking drugs, smugglers are also paid to help illegal aliens cross the border. However, the short barrier — which runs about 18 feet high and is made of concrete and fencing — has deterred smuggling activity in some parts of the area.
Illegal alien smuggling organizations and drug smuggling organizations are very well organized in their operations along the border, Rodriguez added. The organizations deploy scouts on each side of the border to conduct surveillance and carry out well-coordinated smuggling operations in order to get past security, he said.
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In some cases smugglers will send decoy groups of undocumented immigrants or drug traffickers to distract agents from a larger group of illegal aliens or drug smugglers that the criminal organizations are trying to pass through the area, Rodriguez said.
Agents on the ground must also deal with assaults, which spiked in 2017. The number of assaults against border patrol agents jumped from 584 in fiscal year 2016 to 847 in fiscal year 2017, according to CBP data.
Agents tracking suspects near the border, Rodriquez explained, are often attacked by armed narcotics "mules" that suddenly appear from the brush.
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While the US border agency saw a decrease in the number of individuals arrested in 2017, he noted, the numbers increased significantly this year — including a 300 percent spike in apprehensions of MS-13 gang members.
On Monday, Mexican Foreign Affairs Secretary Luis Videgaray and US Department of Homeland Security Secretary Kirstjen Nielsen met in Mexico City where they discussed immigration and border security issues, the US embassy in Mexico said in a statement. Later in the day, the Mexican foreign ministry announced that Mexico and the United States signed three agreements to facilitate cross-border trade, including related to cargo inspections and compliance.
Last week, Trump signed a spending bill that includes $1.6 billion in appropriations to construct a wall on the US-Mexican border. On March 13, during a visit to California to view border wall prototypes, Trump said he would prefer to erect a barrier with see-through capability.
READ MORE: Trump Inspects Wall Prototypes for US-Mexico Border in California
Curbing illegal immigration, combating drug trafficking, and cracking down on transnational gangs have been some of US President Donald Trump's signature pledges so far during his presidency and on the campaign trail.