Authorities on both sides of the US-Mexico border have shut the 10th drug-smuggling tunnel to San Diego in more than a decade - a passageway Mexican authorities on Thursday attributed to the cartel of fugitive kingpin Joaquin "El Chapo" Guzman.

The tunnel, originating from the Mexican border city of Tijuana, is about eight football fields in length, with the last quarter-mile crossing US territory before ending beneath a carpet warehouse in the busy Otay Mesa industrial district of San Diego.

The tunnel was uncovered through intelligence gathered by US federal agents who infiltrated a Mexican drug-smuggling ring during the past six months, according to Laura Duffy, the US Attorney in San Diego.

Ventilation, rail system

It marked the 10th subterranean passageway from Mexico to Otay Mesa discovered since 2002. Like those and dozens of others found along the nearly 3,200-km border in the last decade, the tunnel was equipped with lighting, ventilation and a rail system for moving goods.

Two Mexican government security officials, speaking on condition of anonymity, said the latest passage belonged to the Guzman-led Sinaloa drug cartel.

Duffy said US officials were less certain that Sinaloa was behind the new tunnel, based on the comparatively unfinished, dangerous nature of the shaft on the US side.

"We usually see ladders going down and staircases," she said. "This particular tunnel drops 32 to 35 feet (9.8 to 10.7 meters) straight down."

Duffy confirmed that US federal agents moved to seize control of the tunnel at the north end on Wednesday after a shipment of 2 tons of marijuana arrived there. Six men were arrested, two of whom were to be arraigned on federal drug-smuggling charges.

Mexican agents seized 10 tons of marijuana awaiting shipment through the passage at the Tijuana side, and authorities expect to find more contraband when a thorough search of the tunnel is made, Duffy said.

Guzman, the world's most wanted drug trafficker, escaped in July from a Mexican maximum-security prison through a tunnel that surfaced right inside his cell.

A massive manhunt has since been launched to capture him.