EL PASO, Texas (Border Report) — Two Mexican nationals attempted to sneak more than $89,000 in cash south of the border without declaring it, U.S. Custom and Border Protection said.

Border officers conducting outbound inspections at the Stanton Stree Bridge in Downtown El Paso picked, for a routine inspection, a vehicle driven by a 22-year-old Mexican national. Neither the driver nor the 46-year-old passenger, also a Mexican citizen, declared the cash, CBP said.

With the help of a CBP currency-firearms detector canine, CBP officers located multiple stacks of cash hidden within the vehicle.

CBP officer seized a total of $89,031 as well as the vehicle while turning over the two individuals to special agents with U.S. Immigration and Customs Enforcement’s Homeland Security Investigations

CBP warned travelers that they must file a report to transport, including through mail, any amount of currency or other monetary instruments exceeding $10,000 into or out of the United States.

The rules state that those who fail to comply face civil and criminal penalties, which could lead to forfeiture of the money.

“CBP officers routinely conduct outbound inspections on traffic headed into Mexico,” CBP El Paso Port Director Ray Provencio said in a statement. “The outbound inspections are designed to identify and stop a variety of items including weapons, ammunition, and unreported currency.”