A teenager has been arrested after a child “fell from a height at the Tate Modern” in London, police said.
The incident happened at about 3pm on Sunday in front of shocked witnesses.
A Met Police spokesman said: “Officers are in the vicinity of the Tate Modern following an incident this afternoon.
“A child fell from height and is being taken to hospital by London’s Air Ambulance.
“We await an update on his condition.
“A teenager has been arrested in connection with the incident.”
Visitors have been told to stay indoors as emergency services carry out an investigation.
Kacper Kula told the Standard he left the Tate about half an hour before it went into lockdown and was sitting in Calluocos, a neighbouring restaurant as the incident unfolded.
He said: “The ambulance helicopter landed next to the restaurant at 3pm, a lot of ambulances were already there and a lot of fire fighters appeared shortly after.”
Greg Richie wrote on Twitter: “Nobody being allowed in or out of the Tate Modern for the last 20 minutes. Plenty of police and ambulances arriving, and a helicopter just landed. Not clear what’s happened.”