(NewsNation) — Cartels are using drains to smuggle people into the U.S., creating another issue for the Biden administration as it relates to the border crisis.

The storm drain system in El Paso, Texas, has become an unexpected battleground in the ongoing fight against illegal immigration and human smuggling.

Border Patrol agents in El Paso are facing new challenges as smugglers use these underground networks to move migrants.

How is this happening?

Sources inside Juarez tell NewsNation that since President Biden’s latest asylum crackdown, migrants are turning to smugglers as a means of illegally entering into the U.S.

The storm drain system in El Paso is extensive; spanning over 300 miles. These drains, obviously designed to manage storm water, are being exploited by smugglers to move migrants.

Migrants have been using tunnels and storm drains to avoid capture since at least the 1960s, but smugglers have turned these underground networks into dangerous routes. Migrants, including children, are forced into these drains without knowing where they are going.

They rely entirely on the smugglers, who can be very unreliable and put them in great danger.

Who is fighting back against the cartels?

The task of stopping these smugglers falls to the Border Patrol’s Confined Space Entry Team; otherwise known as CSET. 

This specialized team faces numerous challenges, including toxic gases, snakes, and the risk of flash floods, when they go looking for signs of recent activity.

As CSET has been sweeping these drains recently, it has found an increase in entries. The team is looking to rescue migrants, as well as locate smugglers.

They say smugglers use tools like electric cutters and gas-powered saws to create new entry points into drains.

What happens next?

Sources in Mexico tell NewsNation they expect to see more migrants moving through these tunnels.

It coincides with Mexico stepping up its efforts to fight against the migrant smuggling trade. For now, smugglers are cashing in big time at the border.

CSET agents have to continue to navigate the toxic gases inside the tunnels, as well as combatting compromised Mexican authorities, sources tell NewsNation.