The man stopped by the authorities at a Lagos airport on a Wednesday in mid-August said he’d come to Nigeria to open a restaurant. Drug-enforcement agents had a different story.

They’d spent months hunting the Mexican national suspected of having links to an industrial-scale methamphetamine lab secreted in the country’s southwest before catching him as he tried to flee, authorities said. He denied any role in manufacturing the drug.

The arrest of Arturo Carrera Loaiza led them to a second suspected site in Ebonyi state 430 miles away — the fourth meth lab found in Nigeria in six months, and the third with alleged Mexican involvement. That’s more than the authorities dismantled in any previous year since the first one was discovered in the West African nation 15 years ago, according to the National Drug Law Enforcement Agency’s spokesman Femi Babafemi.

Together, the busts point to a shift in the global meth trade: Africa is emerging from its traditional role as a trafficking corridor into a production base, generating proceeds that can help criminal groups acquire weapons and ammunition.

“The broader significance is that we may be seeing a change from Africa being primarily a transit environment for the international drug trade toward parts of the continent becoming locations where criminal networks can establish and operate parts of the production chain itself,” said Ebunoluwa George Ojo-Ami, an intelligence manager at Agwe Global Group, a maritime risk consultancy and security firm.

For decades, large-scale production has been concentrated in places including Mexico, Myanmar and parts of Europe. Now, as authorities tighten controls on major cartels and trafficking routes, some production is turning up thousands of miles away in Africa, where criminal groups can exploit weak enforcement, existing smuggling networks, graft and cheap labor. The drugs are largely destined for Europe, Oceania and Asia.

“Criminal networks gravitate toward wherever governance, security or judicial capacity gaps are widest,” said Cheikh Ousmane Toure, the United Nations Office on Drugs and Crime representative in Nigeria.

Beyond the lab in Ebonyi, other facilities have been uncovered in Imo, Oyo and Ogun states — close to maritime gateways that connect Africa’s most-populous nation to shipping routes across the Atlantic Ocean and beyond.

The Ogun operation, hidden in a forest in southwest Nigeria, was by far the largest clandestine meth lab found in the country to date, according to the authorities. More than 2.4 tons of the drug and precursor chemicals valued at 480 billion naira ($361 million) were seized, and three Mexicans and seven Nigerians arrested.

Africa offers a major opportunity for trafficking groups “looking for diversification in order to build up continuity and resilience,” said Ian Ralby, a fellow at the Center for International Maritime Security.

At least three clandestine meth labs have also been disrupted in South Africa, with two involving Mexican nationals, compared with one last year, according to data compiled by Bloomberg from police and prosecutorial statements. In recent years, production facilities have also emerged in Kenya and Mozambique.

Meth production isn’t tethered to a specific geography as it is a synthetic, making it easier for criminal networks to move locations. Its highly addictive nature also helps sustain demand.

The shift in production can partially be attributed to the US’s campaign against groups including the Sinaloa Cartel and Cártel de Jalisco Nueva Generación, major producers and traffickers of meth.

Heightened enforcement against criminal syndicates is forcing them to consider “where else they can turn to, and then they see Africa as one of those places,” Babafemi said.

The Nigerian busts also show how US counter-narcotics efforts are extending beyond traditional trafficking corridors, with American agencies providing intelligence and other support to African authorities.

Dagvin Anderson, the head of US Africa Command, told US lawmakers in May that over the past two years, the country had helped African governments uncover or alerted them to suspected drug operations. Of the 12 labs shut down, he said, 11 had Mexican cartel members on site.

The expansion carries risks beyond the meth market. Babafemi said proceeds from illicit drugs in Nigeria can be used by criminal groups to acquire weapons and ammunition.

Mexican criminal organizations also have experience in cocaine trafficking and processing, raising the prospect that an established presence in Nigeria could eventually extend to local production, said Andrew Cunningham, head of sector for crime, markets and precursors at the European Union Drugs Agency.

Such a foothold could deepen the security risks for Nigeria already contending with terrorism, banditry, kidnappings and separatist violence.

“It undermines the rule of law and can disrupt governance because there is so much money and there is organized crime involved,” Cunningham said. “It’s very disruptive and it corrodes the fabric of society.”