Nigerian drug agents say they have arrested four Mexicans helping Nigerian criminals build a "super-lab" capable of producing billions of dollars' worth of methamphetamine.

Spokesman Mitchell Ofoyeju of the National Drug Law Enforcement Agency says the warehouse capable of producing up to 4,000 kilograms (8,800 pounds) a week of the synthetic drug is the first discovered in West Africa. He says methamphetamine sells for up to $6,000 a kilo in Nigeria but as much as $300,000 a kilo in the Asian markets favored by Nigerian drug dealers.

Ofoyeju said in an interview Monday that last week's arrests of four Mexicans and four Nigerians in simultaneous raids in three southern towns smashed "a major drug syndicate" and the first industrial-scale crystal meth production line in West Africa.