One man was injured as two groups shot at each other during a festival in an east London park.
The shooting happened at 1530 BST in London Fields, Hackney, at the junction of Shrubland Road and Forest Road.
The wounded man has sustained life-threatening injuries, the Metropolitan Police said.
A BBC journalist who saw the incident said there was an outbreak of shooting between two groups. The injured man was shot in the stomach.
No arrests have been made. Paramedics and police officers remain at the scene.
Hundreds of families had gathered for the day-long festival, organised by Hackney Council, to preview other events to be held in the borough’s parks.
The BBC journalist said he saw several men on a bench get up and run.
They were followed by another group of men and shots were exchanged.
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