A coronavirus testing centre has been forced to close early after stones were thrown at staff, according to police.
Staff at the Rotherham site, which is in the car park of Maltby Leisure Centre, were attacked on Tuesday night by young people throwing stones.
South Yorkshire Police said it was "yet another night" the station had to close early following anti-social behaviour.
The Department for Health and Social Care, which runs the site, said the attacks were "abhorrent".
The South Yorkshire force's Rotherham South Neighbourhood Policing Team said "local youths" were thought to be responsible for the attacks.
A dispersal order had been in place between 24-26 March due to "ongoing anti-social behaviour" by groups gathering and assaulting staff, police said.
Officers said such behaviour "will not be tolerated" and "positive action" would be taken when those taking part were identified.
A Department of Health and Social Care spokesperson said the attacks and abuse towards staff were "unwarranted".
"They are performing work crucial to stopping the spread of Covid-19 and helping us all return to a more normal way of life," the spokesperson said.
The walk-in site was supposed to be open for pre-booked appointments from 08:00 to 20:00 seven days a week, according to Rotherham Council.
A council spokesperson said: "We are disappointed staff at the test site, who have been providing the borough with an essential service throughout the pandemic, have been subjected to anti-social behaviour."
The authority was working with partners to put "a range of measures" in place to ensure the Maltby site was safe for everyone, the spokesperson added.