Maddington residents were forced to evacuate their homes last night before police arrested an armed man inside a suspected drug lab.
Police spokeswoman Ros Weatherall said the Tactical Response Group was called to a house on Kenwick Road after reports a man with a firearm was holed up in a house.
Officers evacuated neighbours and cordoned off the area before arresting a 38-year-old man, Ms Weatherall said.
She said the alleged offender followed police instructions without any confrontation.
Police searched the house and a shed and discovered a hydroponic cannabis set-up and a  gas bottle containing ammonia.
Ammonia is used to manufacture methamphetamine.
Fire and rescue services also attended the scene.
The man was charged with cultivating a prohibited plant with intent to sell and supply.
Last night's arrest was the third suspected drug lab in the past two weeks which police have uncovered.
pilot was arrested on Friday after police found chemicals and glass instruments used for making drugs inside a hangar at Jandakot Airport.
On October 29, a woman was charged in relation to a suspected drug lab in Huntingdale where residents were also forced to flee their homes.