A 14-year-old boy has been arrested on suspicion of the murder of another teenager who died after being attacked in Gateshead, Northumbria Police said.
The force said a murder investigation has been launched after the suspected assault took place on Monday night after 8pm.
Officers said they were alerted by the ambulance service to reports of a teenage boy, also 14-years-old, being seriously injured in the area of the Springwell Estate in Gateshead.
Emergency services attended the scene and treated the teenager who "had suffered an injury consistent with having been caused by a bladed article," according to police.
A statement from Northumbria Police read: "He was taken to hospital where, despite the best efforts of medics, he sadly passed away in the early hours of this morning.
"His family are being supported by specially-trained officers at this devastating time."
They added that an investigation was "immediately launched" and that a 14-year-old boy has been arrested on suspicion of murder.
He remains in police custody for questioning.
The force said that a 13-year-old girl has also been arrested on suspicion of assisting an offender.
Chief Superintendent Helena Barron said: "A teenage boy has sadly died and his family have been left devastated beyond belief. Our thoughts are very much with his loved ones at this time and we are supporting them in every way we can.
"We are determined to find out exactly what happened and a full investigation is ongoing into the circumstances surrounding this tragic incident.
"We have arrested two teenagers in relation to the incident and officers remain in the area to carry out a range of enquiries and offer reassurance to the community.
"While incidents of this nature are rare in our region, whenever they do occur we are committed to bringing those responsible to justice."
She added: "We would ask the public not to speculate on details of the investigation.
"What might seem like an innocent post on social media to you, could in reality disrupt an on-going investigation and cause further upset to the family of the victim.
"We would ask that if you did see something or have information in relation to what has happened, please come forward directly to officers."
Northumbria Police and Crime Commissioner Kim McGuinness said: "It's devastating that our region has lost another young person to serious violence and my thoughts are with the victim's family who will be experiencing unimaginable pain.
"This should never have happened and it now sits with our police to carry out extensive enquiries to establish the full circumstances that have led to the senseless loss of a young life.
"I recognise the shock and concern that will no doubt be felt across local communities and I know officers will be on hand to offer reassurance."