Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

LAGOS, Nigeria — Nigerian drug agents arrested four Mexicans who were allegedly helping build a "super-lab" capable of producing billions of dollars' worth of methamphetamine, the National Drug Law Enforcement Agency said Monday.

Spokesman Mitchell Ofoyeju said it was the first industrial-scale production of crystal meth found in West Africa, and possibly on the continent.

"The Nigerians invited the Mexicans in to leverage their expertise in these industrial-scale, high-yield productions," said Ofoyeju.

The Morning Rundown Get a head start on the morning's top stories. This site is protected by recaptcha

The warehouse in southern Delta state could produce 8,800 pounds a week of the synthetic drug, which sells for about $2,700 a pound in Nigeria but as much as $140,000 a pound in the Asian markets favored by Nigerian drug dealers, Ofoyeju told The Associated Press. Most goes to Singapore and Malaysia.

Related: Cross-Border Meth Trade Booms Amid Mexico's 'War on Drugs'

The lab completed a first successful production in February and the agents raided it as the Mexicans were producing a second run, Ofoyeju said. Only 3.3 pounds of meth was recovered with 200 gallons of liquid methamphetamine.

Mexico's Foreign Relations Department said its embassy in Nigeria was working with local authorities to confirm the suspects' identities and nationalities and determine their legal status.

The raid came after an undercover operation that also netted the arrests of four Nigerians last Wednesday. The eight arrests happened in simultaneous raids in two southern towns and the commercial capital, Lagos.

Separately, Nigeria's drug enforcement agency announced the weekend arrest of suspected drug baron Tochukwu Harris Ubah in connection with the seizure at Lagos port of 1,270 pounds of crystal meth and ephedrine — used in small-scale production. It was bound for Durban, South Africa.

The first crystal meth labs in West Africa were discovered in Nigeria in 2011, and 10, smaller than industrial scale, have since been dismantled. The West African Drug Commission has warned that drug lords are corrupting politicians and law enforcers, and even running for office themselves.