A man has been arrested on suspicion of murder after a teenage boy was stabbed to death near a pub, police said.
The 17-year-old was knifed twice in the chest and although paramedics fought to save his life at the scene in Hastings, East Sussex, he died.
Sussex Police said the 31-year-old suspect from the nearby town of Rye was being held in police custody and said the stabbing did not appear to be a random attack.
Emergency services were called to the scene near The Shah pub in Mount Pleasant Road at around 3.20pm and the street and surrounding areas were sealed off while inquiries were carried out.
Police also appealed for anyone with information about the stabbing to come forward.
Superintendent Trevor Botting, head of crime and operations for East Sussex, said: "This is a tragic incident and one that has shocked the local community. Our thoughts are with the victim's family, who understandably are devastated by the events of this afternoon.
"It is too early to speculate as to the circumstances of this tragedy, although early indications are that this was not a random attack.
"Our job now is to gather as much information as we can to build up a picture of what happened and to identify those responsible.
"We need the public's help to do this and would urge anyone who thinks they have information but has not yet contacted police to do so as a matter of urgency."
He apologised to local residents for the police cordons, adding: "We would like to thank them for their co-operation and patience."
A South East Coast Ambulance spokesman said the teenager was treated for two stab wounds to the chest.
A Sussex Police spokesman said: "Paramedics fought to save the boy who had been stabbed in the chest, but sadly he died."
Anyone with information is asked to contact Sussex Police on 101, quoting Operation Chinook, or Crimestoppers anonymously on 0800 555 111.