Two boys have died after a "serious incident" in Sheffield which also left four other children in hospital.
The six children were taken to hospital after police were called to reports of concerns for safety at a home in Gregg House Road, in Shiregreen, at 7.30am.
South Yorkshire Police later confirmed two boys, aged 13 and 14, died in hospital.
Four other children, aged 11, 10 and three and one other aged seven months remain in hospital receiving treatment and are conscious.
Police confirmed their conditions are not life-threatening.
Officers said the incident was not a shooting and is not related to the nearby school but have not revealed the exact nature of it.
Speaking at the scene, Superintendent Paul McCurry said: "I think it's really important that I reassure the wider community that there's no wider risk.
"The investigation is at a very early stage and detectives are working closely with a number of different lines of inquiry.
"Our detectives are supporting the family."
The senior officer added: "I'm aware of wider speculation regarding the use of weapons. At the moment there is no wider risk to the community in Sheffield."
"At the moment there is no wider risk to the community in Sheffield."
A 37-year-old man and a 34-year-old woman have been arrested on suspicion of murder in connection with the incident, police said.
They were unable to reveal the relationship of the children to each other or the adults.
Post-mortems on the boys who died will be carried out later this afternoon.
The scene is understood to be near Hartley Brook Primary Academy, with the air ambulance landing in the school playground.
A cordon was partially lifted in the area by early afternoon, but officers and forensics teams continued to examine a semi-detached council-type house.
Police said there would be extra patrols in the area across the weekend but they are not looking for anyone else in relation to the incident.
Detective Chief Inspector Simon Palmer, investigating, said: “Detectives and specialist officers remain in the Gregg House Road area carrying out enquiries and we are working hard to ascertain the exact circumstances surrounding this incident.
"We will remain in the area this afternoon and into the evening carrying out enquiries and providing reassurance.
"I appreciate the events of this morning have caused concern locally but I’d like to reassure you that there is no wider risk to the community."
At the scene, people brought flowers and balloons to the police cordon.
One woman laying flowers said: "It's just so sad. I hope the rest of the kids get well."
Gregg House Road resident Aaron Brunskill said neighbours came out into the street at about 8am to find around 15 police cars and four ambulances.
He said: "The police weren't telling us anything. I know there's children there. I've just seen them walking back to the shops and that's all I know."
"There were four ambulances. Everyone got took away in an ambulance. I don't know if the air ambulance was used."
Local Labour MP Gill Furniss said: "I'm deeply saddened by the tragedy today in Shiregreen.
"My sympathies are with the loved ones of the children who have lost their lives. Shiregreen is a strong community - I know the whole area is shaken by what has happened.
"My thanks to police and NHS staff for their response."
Anyone with information is asked to call 101 or Crimestoppers anonymously on 0800 555111 quoting incident number 122 of 24 May 2019.