An estimated $800 million worth of marijuana has been seized following a massive raid on illegal grows on public lands deep in Northern California's pot country, authorities said Tuesday.

The three-week effort, known as Operation Full Court Press, to purge the Mendocino National Forest of illegal gardens, seized more than 632,000 marijuana plants. The operation also led to 132 people being arrested as 118 were booked on federal and state charges and 14 were detained on immigration violations.

Several Mexican-based drug trafficking organizations were behind the illegal grows, Department of Justice spokeswoman Michelle Gregory said.

In previous years, officials have blamed Mexican drug cartels for some of the state's largest growing operations, but Gregory stopped short of making that claim.

"We've been looking at all of these groups for several years," Gregory said. "We're continuously trying to figure out who these guys are and their ties."

The nearly $800 million in marijuana plants seized is a conservative estimate, said John Heil, a regional spokesman for the U.S. Forest Service. The amount is based on a street value of marijuana being worth about $2,500 per pound, Heil said.

Authorities have said a focus on the Mendocino National Forest this year stemmed from citizen complaints a year ago about an increasing number of confrontations with armed guards protecting pot grows.

The 1,400-square-mile forest covers six counties in a region of mountains and forests known as the Emerald Triangle due to its high concentration of pot farms.

Officials said that the latest raids also seized nearly 2,000 pounds of processed marijuana, 38 guns and 20 vehicles. Agents also removed trash and chemicals as well as about 40 miles of irrigation line that damage forestland and waterways.

"It has been very successful operation for all of the agencies involved," Heil said. "We tried to hit an area that seems to have a significant problem."

The operation conducted by local, state and federal agencies was part of an annual summer effort to eradicate marijuana from public lands across the state.