A four-year-old boy who was found injured in the street is believed to have been stabbed, police have said.
The youngster, who has not been named, was rushed to the Queen's Medical Centre in Nottingham after he was found with serious injuries in Frederick Street, Mansfield, at about 1.30pm on Monday.
The boy's parents have been with him at the hospital, where he is conscious and stable.
A 51-year-old man has been arrested in connection with the assault and will be questioned by officers, a spokesman for Nottinghamshire Police said.
He added: "We believe this is an isolated incident and we do not think any other parties are involved. We will be interviewing the man in custody later today.
"Specialist support is being provided for the boy and his family, while house-to-house inquiries and a full forensic examination of a property in Frederick Street will be carried out today."
Anyone with any information about the incident is asked to contact Nottinghamshire Police on 101 or Crimestoppers on 0800 555 111.
The father of the injured boy told the Mansfield Chad that his son was now out of intensive care and was expected to be discharged from hospital in the coming days.
The man, who was not named by the newspaper, said he was shocked at the incident and described his son as a friendly little boy.
"He is a bright lad, sprightly and everybody knows him," the father said.