An emergency siren usually reserved to warn of an imminent natural disaster rang out in Austin, Texas, as authorities face an explosion of Covid-19 hospitalisations.
The emergency alert system was activated on Saturday to “implore the public to do more to fight Covid-19”, Austin Emergency Management said on Twitter.
It warned residents of the Texas state capital to wear a mask in public, get vaccinated and stay away from crowds.
As of Sunday, there were 3,438 active reported cases of Covid in Austin-Travis County, with 510 hospitalisations, 184 people in ICU and 102 on ventilators, according to the Covid-19 surveillance dashboard.
Austin-Travis County Medical Director Dr. Desmar Walkes told CBS Austin the situation was “critical”.
“Our hospitals are severely stressed and there is little we can do to alleviate their burden with the surging cases,” Dr Walkes said.
“The public has to act now and help or we will face a catastrophe in our community that could have been avoided.”
The Delta variant has cut a swathe through Texas, Louisiana and Florida in recent weeks, causing new daily case rates to surge to their highest levels since the pandemic began.
The new Covid-19 strain has impacted children, with Houston pediatric units unable to take new patients last week.
An 11-month-old girl suffering from Covid had to be airlifted from Houston to a hospital 150 miles away in Temple.
Texas Governor Greg Abbott has refused to reinstate a state-wide mask mandate he lifted in March.
