At least six foreign workers were rescued Thursday from an underground cigarette factory in Spain. They were found trapped in squalor with restricted oxygen supply, police said.

Police were in the dark about the factory’s operations underneath Monda, a mountain village in Malaga in southern Spain. They worked with Interpol in a sting operation dubbed “Hannibal” to spot the factory located under horse stables. Police arrested 20 people, 12 of them suspected of running the factory. All 12 were British while the rescued workers were Ukrainian and Lithuanian nationals, BBC reported.

The factory, capable of churning out 3,500 cigarettes in an hour, was hidden in a maze of tunnels accessible only through a trapdoor entrance, the Interior Ministry of Spain said in a statement.

The factory was also equipped with machinery for packaging and had an indoor cannabis farm, according to police documents.

The arrests of the suspected kingpins left the workers gasping for breath as no one was there to activate the oxygen generator. They shouted and banged on the trapdoor, thereby catching the attention of the police.

"Once inside, the police agents saw with great surprise the six workers who were struggling to breathe in an utterly insalubrious atmosphere," police said. "If the officials had not found the clandestine factory in time, the lack of oxygen would have soon made ... the underground conditions incompatible with the survival of the workers who were there."

Police said the factory owners made “enormous security measures” to keep the factory away from prying eyes. They confiscated 153,000 packs of cigarettes, more than 17 tonnes of rolling tobacco, 144 kg (0.16 tons) of marijuana and 20 kg of hashish.

Police were probing further into the matter. The six workers were freed pending the outcome. The detainees will face punishment in terms of the degree of their responsibility.

The investigating agencies said it was the first underground illegal cigarette factory uncovered in the European Union.

Do you know what’s in your cigarettes? Photo courtesy of Pexels, Public Domain