In this photo provided by the US Customs and Border Protection, a silver Jeep Cherokee that suspected smugglers were attempting to drive over the US-Mexico border fence is stuck at the top of a makeshift ramp.

Jeep goes to great lengths to boast about how its vehicles are 'Trail Rated', and few would deny that its 4x4 vehicles are highly capable in the bush.

Nonetheless, there is one thing that the American company has never pointed out - the fact that its SUVs are not US border fence rated.

Two Mexicans found this out the hard way after trying to drive an older-generation Jeep Cherokee over the US-Mexico border fence on a set of makeshift ramps.

As common sense would dictate, a pyramid-shaped ramp entails a rather extreme breakover angle, and the end result was a Cherokee wedged at the top of the 4.3-metre-high fence.

The US Custom and Border Patrol agency said that the two suspects managed to flee back to Mexico after US border guards spotted the bold attempt to scale the fence in the early hours of Tuesday.

"Agents patrolling in the Imperial Sand Dunes area encountered a silver Jeep Cherokee attempting to drive over the International Boundary fence using a makeshift ramp that was not quite up to the task," said a CBP statement.

"When the vehicle made it to the top of the ramp, it became high-centered.... As agents arrived on scene, two subjects fled into Mexico. After removing the Jeep from the fence, agents seized both the vehicle and the ramps," it added.

US authorities have long battled to contain illegal immigration and smuggling across the southern border with Mexico, and the region is plagued by violence linked to traffickers of drugs and humans.

Strangely, this is not the first time something like this has happened. In 2007 a border patrol agent was killed near the area where the car got stuck on ramps, when he was deliberately struck by a vehicle as he tried to deflate its tires.

Tunnels underneath the border are regularly unearthed, some of them with highly sophisticated equipment and ventilation systems, and entrances typically concealed in warehouses or other structures near the frontier. -IOL & AFP