In a statement issued this morning, South Yorkshire Police said two arrests have also been made.
Emergency service were alerted to the incident in Gregg House Road, Shiregreen, at 7.30am.
At the height of the incident was an air ambulance, numerous ambulances and multiple police vehicles at the scene.
A huge police cordon remains in place.
The statement says: “Police were called at around 7.30am today to reports of concerns for safety at a property on Gregg House Road, Shiregreen.
“Yorkshire Ambulance Service and Yorkshire Air Ambulance have attended and transported six children to hospital.
“Two people are under arrest.
“There will be a significant police presence at the scene throughout the day as officers continue enquiries.
“A cordon is in place and buses are being diverted from the area.
“This incident is ongoing.”