Drug smugglers converted a van into a makeshift petrol tanker to refuel the high speed launches the used to smuggle cannabis resin from Morocco into Spain.
Organised crime networks require large amounts of petrol for their vessels and Spanish law enforcement has been working to disrupt their supply chains.
The ruse was discovered by the Guardia Civil when they seized the vehicle, which had been fitted with two plastic tanks each carrying 1,000 litres of fuel.
Under Spanish law, fuel can only be carried in cans with capacity for up to 60 litres, and up to a maximum of 240 litres per vehicle. Anything over that would require a permit for hazardous substances.
Three men face hefty fines for the incident.
In a separate operation, Spanish police officers in the Puerto Santa Maria arrested a gang whose three members stole four-wheel drive vehicles for use by drug smuggling networks in the Campo, namely in Algeciras and La Linea.
Officers recovered 15 stolen vehicles and seized 2.2 tonnes of cannabis resin, along with a rifle and jewellery worth 8,000 euros.
Video footage released by the Policia Nacional shows the moment the gang was arrested by armed plainclothes officers.
Police suspect the gang of involvement in the theft of 15 vehicles, 14 residential burglaries, drug offences and a robbery.