ALBUQUERQUE, N.M. (AP) – The U.S. attorney’s office says it destroyed a quarter-million plants during marijuana eradication efforts at 21 farms in the Shiprock area of the Navajo Nation in northwestern New Mexico.

In a news release Monday, federal prosecutors say the raids by U.S., state, and tribal law enforcement authorities took three days to carry out, starting on Nov. 9, and involved more than 1,100 makeshift greenhouses. In one instance, 1,000 pounds (450 kilograms) of processed marijuana was discovered under a tarp. The news release makes no mention of arrests or charges.

In October, more than a dozen people were arrested on drug charges at a motel in the area. Authorities alleged the suspects were trimming marijuana plants in multiple motel rooms as marijuana was being stored in other rooms. Investigators were trying to determine whether the suspects were tied to the hemp operations.

The Navajo Nation just weeks ago sued nearly three dozen people, accusing them of illegally growing hemp or marijuana on the reservation. The lawsuit claims that the operations are contaminating the tribe’s water, land, and other natural resources. It was the second such lawsuit the tribe’s Department of Justice has filed this year.

The tribe does not have a regulatory system for industrial hemp on the vast reservation that spans parts of Utah, New Mexico and Arizona.

New Mexico has no legal market for recreational cannabis and limits medical marijuana producers to 1,750 plants per licensed producer.

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