Three children are in hospital with stab wounds after police were called to a home on Monday morning.
A woman has been arrested on suspicion of attempted murder after four people including three young children were found seriously injured at a house in Huddersfield, West Yorkshire Police said.
Police were called to an address on Walpole Road at about 8am after receiving a report of concern for safety from the ambulance service.
Officers attended the scene at which three young children, two boys and a girl, and a woman were found having suffered serious injuries, believed to have been caused by a bladed weapon.
All four were taken to hospital for treatment and continue to be treated for those injuries.
A woman has now been arrested on suspicion of attempted murder as part of the investigation.
DCI Sam Freeman of the Homicide and Major Enquiry Team, said: “Enquiries are ongoing today into what has clearly been a serious and distressing incident in Huddersfield and we fully appreciate the concern it will cause in the local community.
“Detectives are conducting enquiries to determine the exact circumstances of what has taken place and an arrest has now been made as part of those investigations.”
Chief Inspector Rebecca Calpin of Kirklees Police, said: “Reassurance patrols are taking place in the local area by officers from the Huddersfield Neighbourhood Policing Team and will be continuing throughout the day as Kirklees officers work to support colleagues from our HMET team.”