A naked Australian man armed with a pistol climbed up a 10-metre-high billboard in Perth and shouted at onlookers below for nearly four hours, bringing the entire city police unit on alert.

The shaven-headed man, who appeared to be in his 30s or 40s, climbed on to the advertising billboard at about 2 p.m. Saturday and yelled at onlookers, while pacing up and down the billboard, Perth Now reported.