OAKLAND -- A refrigerator full of packaged marijuana caught fire Thursday morning inside an East Oakland warehouse, authorities said.

The fire was reported at 6:01 a.m. at the building in the 400 block of Pendleton Way, not far from Oakland International Airport.

Battalion Fire Chief Coy Justice said a 23-cubic-foot refrigerator caught fire for a still undetermined reason, causing the sprinkler system to activate.

About 30 firefighters responded and had the smoky fire contained in 20 minutes. No one was injured.

Inside the refrigerator, firefighters found marijuana packaged in plastic cylinders, Justice said. The exact amount and value of the weed was not immediately determined. Information on the owner of the site was not released.

No more marijuana was found at the site, officials said. Police are investigating.

Check back for updates.