Gwent police received a call from the ambulance service to a house on Salisbury Close, Newport this morning at about 8am.
Two children, a 7 year old boy and a 16 month old baby girl, suffered injuries and are currently at the Royal Gwent Hospital receiving treatment.
A 27 year old woman, from the Newport area, has been arrested on suspicion of attempted murder and has been taken to the Royal Gwent Hospital where she is receiving treatment for injuries.
A knife has been recovered from the scene.
Police say they are not looking for anyone else in connection with the incident at this time.
