Millions of people in Australia's second-biggest city went into lockdown on Thursday to battle another coronavirus outbreak, as the number of infections worldwide surged past 12 million.
Caseloads and death tolls have risen relentlessly in many of the world's biggest nations, with three million confirmed cases in the United States alone.
In Melbourne, five million people began a new lockdown just weeks after earlier restrictions ended as Australia battles a COVID-19 resurgence, with residents bracing for the emotional and economic costs.
With no vaccine or effective treatment available, experts have warned that social distancing is necessary to contain the virus -- despite opposition in many parts of the world due to economic costs and misinformation.
The state of Victoria, which announced a further 165 new cases Thursday, has been effectively sealed off in an effort to preserve the rest of Australia's success in curbing the virus.
A rush of travelers across the border into neighboring New South Wales on Wednesday has raised concerns those efforts could be torpedoed. Police said about 30,000 cars made the crossing in less than 36 hours.
New South Wales Premier Gladys Berejiklian said two cases of COVID-19 had been identified in the border town of Albury and she warned against travel to or from communities on the state frontier.
"We want to make sure we're flushing out any potential seeding that occurred prior to that spike in cases becoming evident," she told reporters in Sydney.
Queensland state announced Thursday it would turn away all travelers from Victoria -- removing an option that had allowed them to spend 14 days in quarantine on arrival.
In Melbourne, there are concerns over the economic and mental health impacts of the second lockdown, which officials estimate will cost the economy Aus$6 billion ($4.2 billion).
Restaurants and cafes are limited to serving takeaway food, while gyms, beauty salons, and cinemas have been forced to close again.
Residents are restricted to their homes except for work, exercise, medical care or to buy essentials.
Despite the harsh measures, many said they support the restrictions.