Pictures of machete-wielding suspects have been released by the Metropolitan Police as detectives appeal for information about a stabbing in Hyde Park.
Scotland Yard wants to speak to a number of young men after a 17-year-old boy was taken to hospital with stab wounds shortly after 9pm on Tuesday.
His condition has been described as non-life threatening.
Video shared online showed stunned passersby watch on with horror as two gangs, some members of one wearing masks, attack one another with machetes in the central London park, which is popular with the public and tourists.
People could be heard screaming and shouting amid the melee.
On Friday the Met released a series of images from the footage in a public plea to help identify the suspects.
Detective Superintendent Alex Bingley said: “We urge anyone who knows or can identify the men in these pictures to come forward. No piece of information is too small.
“The brazen violence that was witnessed by many people enjoying the sun in Hyde Park was both shocking and unacceptable.”
He added: “We appreciate the images and videos that were widely shared following the incident will have caused concern to people in the area and to those who visit the park regularly.
“I want to reassure the public that we are committed to ensuring our parks remain a safe space for everyone to enjoy. We are doing all we can to track down the individuals involved and bring them to justice.
“Visitors to the park will see an increased police presence and if they have concerns I would encourage them to speak to officers.”
Information can be provided to the police by calling 101, or to Crimestoppers, anonymously, by calling 0800 555 111 and providing the reference CAD7861/01JUN.