Australia's second-largest city Melbourne will remain under stay-at-home orders for at least another week after authorities extended a lockdown Wednesday.

The city entered its sixth pandemic lockdown last Thursday after a fresh Delta variant cluster emerged at a school and spread quickly.

Daniel Andrews, the premier of the state of Victoria, said lockdown rules will be extended until at least August 19, after 20 new cases – some of unknown origin – were detected overnight. "There are too many cases, the origins of which are not clear to us... for us to safely come out of lockdown now," he said.