United States Federal agents have seized about one ton of cocaine and six tons of marijuana.

The stash had been smuggled through a newly discovered tunnel stretching beneath the border between Mexico and the US state of California.

At 800 metres, it is longest such passageway unearthed.

“On the surface I think it fair to say that few would suspect that traffickers were moving multi-ton quantities of cocaine and marijuana in an unassuming way in full view of the world around them with really nothing more than a three-foot hole,” said Laura Duffy, US Attorney for the Southern District of California.

The latest tunnel ran from the bottom of an elevator shaft built into a house in Tijuana to a hole in the ground on the US side enclosed within a fenced-in lot set up as a pallet business. The hole was concealed under a trailer-sized dumpster that smugglers used to move the drugs off the lot, federal officials said.

“Once the dumpster was loaded with drugs, and that was activity