Part of Town Fields remains sealed off by police following reports of a sex assault on a woman.
Officers with sniffer dogs have been scouring the fields and a bench in the middle of the park has been taped off.
A police van is guarding the scene, a short distance from Town Field Primary School and a nearby play area.
South Yorkshire Police were called in after allegations were made of an assault at around 1am this morning.
Local dog walker, Barry Dennis, of Town Moor said: “I saw the police down here early on this morning but I didn’t see or hear anything last night. It is quite a distance from any houses so I don’t know what has happened.”
The cordon has been placed around a park bench and litter bin, with a single beer can visible near the bin.
A woman, who declined to be named, said: “It is very worrying because it is quite near to the school. I suppose with the weather being nice yesterday there would have been a lot of people out on the fields.”
Investigations are continuing.