A riot broke out at an Australian maximum-security prison Tuesday after officials announced a statewide smoking ban in prisons, The Guardian reported, citing sources. About 200 staff were evacuated as police attempted to contain roughly 300 inmates who were involved in the unrest at the Metropolitan remand center in the western suburbs of Melbourne, according to the ABC. Local media reported a group of prisoners had breached an inner perimeter fence and reportedly lit fires as they roamed the grounds. The riot was reportedly in reaction to the state smoking ban that goes into effect Wednesday, but police could not confirm the claim. About 84 percent of the country’s prison population smokes, according to the Australian Institute of Health and Welfare.