PORTLAND, Ore. (KOIN) — Oregon State Police says it seized two firearms and nearly 7,000 illegal marijuana plants during a search of about 40 greenhouses in Klamath County on Wednesday.

Officials from multiple agencies executed a search warrant at a large illegal grow operation off Ferguson Mountain Road, near Beatty, Ore.

The search ended with 6,916 illegal marijuana plants being seized and ultimately destroyed.

Authorities also seized a couple semi-automatic rifles which did not have serial numbers. OSP said both guns were loaded with high-capacity magazines.

The illegal operation allegedly used about 1 million gallons of water that police say was pumped from an illegal well on-site.

An investigation is underway.