A man and a teenage boy were stabbed in Huddersfield before the same 17-year-old was arrested.
Police are appealing for witnesses following a report of two stabbings in the Birkby area last night.
At around 7.10pm, police were called by the ambulance service to the Blacker Road area to a report of a male with a stab wound.
The man, aged 20, was taken to hospital for treatment for serious, but not life-threatening, injuries.
A second male, aged 17, was found nearby with a superficial stab wound.
He has been arrested in connection with the incident.
The incident is believed to have happened in the Blacker Road and Sufton Street area.
Detective Inspector Mark Catney, of Kirklees CID, said: “Our enquiries are ongoing today into the circumstances of this incident.
“Officers remain at the scene and we would continue to appeal for witnesses or anyone with information to speak to officers.
“We believe the assault has happened in the Blacker Road and Sufton Street area and I would appeal for anyone who witnessed the incident happening or anyone who saw the men moving onto Blacker Road to contact officers.
“I would also appeal for anyone who saw a large group hanging around in the area at the time of the incident to contact police.
“We will continue to deal with all incidents involving knives robustly and there will be an increased policing presence in the Blacker Road area today to offer reassurance to the community.”
Anyone with information is asked to contact Kirklees CID on 101, quoting crime reference 13190083228.