The truck and more than 1,800 butane and propane canisters were reportedly stolen from the Repsol depot in the Spanish capital’s Vicalvaro neighbourhood on Friday.
The Barcelona terror attacks in August were perpetrated by a radical Islamic terror cell which had collected more than 100 gas canisters they were planning to use to blow up landmarks in the Catalan capital including the Sagrada Familia.
A police helicopter is said to have been mobilised to help in the search for the stolen truck, a white Nissan Cabstar, and the cannisters.
Respected Spanish daily La Razon said 1,843 canisters had been reported missing, although another report put the total number of canisters taken at 1,600.
The theft is thought to have taken place between 5.30pm and 10pm on Friday, although police were not alerted until yesterday/on Saturday.
Police sources have played down the suggestion terrorists may be behind the theft, saying they believe common criminals are responsible, although detectives are ruling nothing out and experts in tackling Jihadist radicals have been informed as a precaution.
Spain is currently on terror alert level number four.
More than 250 suspected jihadists have been arrested in Spain since the start of 2015 – most of them since it raised its anti-terror alert level to four on a scale of five on June 26 2015.
The terror gang behind the attacks in Barcelona’s Las Ramblas and the nearby seaside resort of Cambrils in August were planning to use butane gas cylinders stored at a house in Alcanar near Tarragona to blow up iconic landmarks including the Sagrada Familia.
More than 20 butane gas canisters were found intact in the wreckage of their bomb factory.
Traces of triacetone triperoxide, a peroxide-based explosive known as TATP or the Mother of Satan which police believe the terror gang were going to use to detonate the gas, were also discovered.
In February a crazed driver sparked terror by driving a stolen truck packed with gas canisters the wrong way down a busy Barcelona ring road after spending thousands of pounds the night before partying with a friend.
Sources investigating the drama told one local newspaper at the time Swede Joakim Robin Berggren, 32, spent more than £16,000 on a 24-hour bender involving drugs, alcohol and prostitutes after jetting to Spain from Russia with a pal a day earlier.
Instead of going to sleep off his hangover at his hotel after his night of debauchery, he took the truck and led police on a two-mile chase which ended with them having to fire seven shots at the vehicle in a bid to force him to stop.
The dramatic chase – which was initially feared to be a terrorist attack echoing those of Nice and Berlin where a truck was used as a weapon – concluded with Berggren’s admission to a psychiatric centre.
He was given a two-year suspended prison sentence in October and allowed back home after paying a fine of nearly £1,000.