​Border police in Mexico and the United States have discovered another drug smuggling tunnel linking the Mexican city of Tijuana with California. The half-mile tunnel was used to smuggle marijuana into the U.S., police said.

It isn’t far from where authorities found a similar tunnel earlier this month, equipped with rails, ventilation and lights, reports the BBC

Police are still investigating, but local media are speculating that the new tunnel — almost 2,600 feet long — could be even more sophisticated than the first.

The tunnel leads from a house in Tijuana to a warehouse in the Amistad district of Otay Mesa, California, according to the federally funded San Diego Tunnel Task Force (they have a Tunnel Task Force? Damn, this shit’s done gettin’ outta hand).

It wasn’t immediately revealed what led federal agents to discover the tunnel. More details on the case are expected.

Several suspects have been arrested as part of the investigation, according to police, and some marijuana has been seized, said Customs spokeswoman Virginia Kice, according to UPI , although authorities did not say how much pot was confiscated.

“Several tons of marijuana” were found inside the tunnel, a military source told AFP

Federal border patrol, Drug Enforcement Administration, immigration, and Customs agents in the tunnel task force arrested seized an undetermined amount of marijuana in a tractor-trailer on U.S. soil, according to authorities.

Mexican police and U.S. agents said they are cooperating in searching the tunnel, where they expect to find more cannabis.

Earlier this month, border police found more than 20 tons of marijuana during an operation centered on a smugglers’ tunnel which had a similar route to the one found on Friday. The first tunnel was less than two streets away from the one discovered Friday.

Authorities have discovered about a dozen of the smuggling tunnels crossing the U.S./Mexico border.

Smugglers are digging the tunnels to defeat increased drug interdiction efforts at the border, according to police.