Media playback is unsupported on your device Media caption Footage shows inside the tunnel, described by officials as "highly sophisticated"

A drug-smuggling tunnel equipped with electricity, ventilation and a rail system has been found connecting San Diego, California, and Tijuana, Mexico.

Authorities seized more than eight tons of marijuana and 325lb (147kg) of cocaine in the discovery.

Officials have not revealed the exact length or location of the recently finished tunnel, but Mexican media report it is near Tijuana's airport.

More than 75 such secret tunnels have been discovered since 2008.

US Immigration and Customs Enforcement (ICE) announced the find on Thursday.

'Just completed'

It was described as "a just completed, highly sophisticated underground passageway", according to an ICE statement.

The tunnel is the eighth discovered just in San Diego since 2006, according to media reports.

In 2010, officials confiscated 22 tons of drugs from a 640m (2,100ft) tunnel equipped with rail tracks stretching from a Tijuana home to two San Diego warehouses.