KEIZER, Ore. (AP) — Police in Oregon say they have arrested seven people in what they call an extensive illegal marijuana growing operation.

Keizer police say the operation was growing cannabis plants and processing marijuana for sale in six houses in residential areas of Salem and Keizer. Children were living in two of the homes.

Police seized 273 1-pound packages of marijuana, with a street value of about $278,000, and 4,085 plants.

The plants, once matured, could have yielded marijuana worth at least $8 million.

All of those arrested were charged with unlawful manufacture of marijuana, unlawful possession of marijuana and attempted delivery of marijuana.