Washington, June 26 (AHN) US Homeland Security Secretary Markwayne Mullin said the Trump administration plans to complete both the primary and secondary border wall system before President Donald Trump leaves office, while expanding the use of smart fencing, drones and surveillance technology to counter evolving tactics used by Mexican drug cartels.

Appearing before the House Appropriations Subcommittee on Homeland Security, Mullin said the administration was adapting its border strategy as criminal organisations increasingly turned to tunnels, drones and other methods to bypass existing barriers.

"The more walls we put, the more we can focus on trafficked areas," Mullin told lawmakers. "We just discovered our first tunnel in years because our wall is being effective. We are pushing them into what we consider chokepoints."

He said the Department of Homeland Security was studying vulnerable sections of the nearly 2,000-mile US-Mexico border while balancing security requirements with concerns raised by border communities.

"Our thing that we're seeing with the wall is the cartels are always changing, and they're a threat," Mullin said. "There's not one inch of Mexico's northern border that isn't covered by a plaza."

He said the department was deploying additional technology alongside physical barriers.

"We're putting in smart fences, which allows us to respond when they're tampering with the wall," he said. "I'll have it done before President Trump is out of office. We'll have the complete primary and secondary wall done."

According to Mullin, the secondary barrier would give Border Patrol agents time to respond after cartels breached the first fence.

"That gives us time, when they cut the fence, we can react before they can get past the secondary wall," he said. "We're using UAS now to put up heat sensors to be able to track them and see what we're dealing with."

The hearing featured bipartisan discussion on border security, although lawmakers differed on the best approach.

Congressman Henry Cuellar, the ranking Democrat on the subcommittee whose district includes part of the Texas-Mexico border, acknowledged the sharp decline in illegal crossings while urging the administration to work more closely with border communities before expanding wall construction.

"I believe in strong border security," Cuellar said. "But it's got to be more than physical barriers."

He argued that technology, intelligence sharing and trained personnel had contributed significantly to improved border security.

"The numbers went down without a single foot of border wall being constructed," Cuellar said. "You've gotta have repercussions at the border."

Cuellar invited Mullin to visit Laredo to discuss local concerns about wall alignment and its impact on private property.

Mullin accepted the invitation.

Immigration and border security have remained central to President Trump's second-term agenda. The administration has sought billions of dollars from Congress to expand border barriers, recruit additional enforcement personnel and deploy advanced surveillance technologies aimed at curbing illegal crossings and disrupting transnational criminal organisations.

Alongside physical barriers, the administration has increasingly emphasised a layered border security strategy built around artificial intelligence, drones, sensor-equipped surveillance towers and other technologies.