ST. LOUIS • Police and federal agents made a series of early-morning raids and arrests in the St. Louis area Tuesday that targeted a major manufacturing and smuggling ring that was bringing in up to 20 pounds of methamphetamine a week, officials said.

The 18-month investigation resulted in the arrest of 36 people and the seizure of 190 pounds of meth worth more than $3 million, one kilogram of heroin, 16 guns and more than $1 million in cash, they said.

Most of the meth came from Mexican “superlabs” and is more than 90 percent pure, said Jim Shroba, head of the Drug Enforcement Administration office in St. Louis. The ring smuggled both drugs and the bulk cash that sales generated, he said.

Shroba said an investigation that began with the arrest of a “mid-level, multi-ounce dealer” in St. Francois County had taken down a “vast conspiracy of people.”

Dana Nichols, assistant special agent in charge of the St. Louis office of the Bureau of Alcohol, Tobacco, Firearms and Explosives, said investigators had not yet traced the seized guns and did not know if they were connected to other crimes. Nichols did say that she expected firearms charges to be filed.