The Australian Capital Territory (ACT) will enter a strict, seven-day lockdown from 5pm tonight following a positive detection of COVID-19 with an unknown source.
The new case is a man in his 20s who resides in Gungahlin, and has been considered infectious in the community since 8 August. Click here for a list of exposure sites.
Chief Minister Andrew Barr said Canberrans had "one opportunity to stamp this out", explaining the only reasons people can leave home would be for essential reasons such employment, health care, getting vaccinated, purchasing essential groceries and supplies, and up to one hour per day of exercise.
"We do not currently know the source of the infection, but extensive investigation has been underway for many hours," the Chief Minister said.
"This is the most serious public health risk that we have faced in the territory this year, and really since the beginning of the pandemic, and it's why we will be introducing a strict lockdown in response," he said, adding mask mandates will also be introduced for outside the home.
"We've said throughout the outbreak that we've witnessed 300 kilometres up the road from Canberra in Sydney, that the lessons we've learned from that and from elsewhere around Australia are that immediate and significant public health responses are needed to get ahead of this Delta strain."
He said 'general' retail would be shut and called on residents not to browse when they go shopping, and to remain within their local community. Hospitality venues will only be open for takeaway.
"So if you live in Belconnen, exercise in Belconnen. Get your groceries, your essential supplies, in Belconnen...do not be travelling across the ACT for exercise or essential supplies," he said.
"This is not an opportunity to go to Bunnings to browse. This is not an opportunity to hang around the local shops. Get in, get what you need and leave.
"Many people will need to travel outside of their district in order to get vaccinated or to work for essential purposes or to access essential health care - that is reasonable and understood, but where a service is available in your local area, please stay in your local area."
It has been more than a year since the last locally acquired case was recorded in the ACT, and 105 days since the territory recorded a case - a diplomat who was in quarantine.
Updated at 12:36pm AEST on 12 August 2021.
Get our daily business news
Sign up to our free email news updates.