A police horse has died while on duty at Notting Hill Carnival, according to Scotland Yard.
The force said it would be investigating after the animal collapsed at around 9pm on Sunday.
It died at the scene despite being provided with emergency care.
The force said in a statement: “It is too early to determine the cause of death. An investigation will now follow.
“Officers form a very close bond with the animals they serve alongside.
“Our thoughts are with all our mounted branch colleagues tonight.”
It came as police made 38 arrests by 7.30pm on Sunday, 10 of which were for alleged assaults.
Other suspected offences included drug possession, criminal damage and possession of offensive weapons.
Two arrests were made for alleged sexual assaults, according to the force.
Millions were expected to attend the carnival over the course of the two-day festival, which has had a two-year hiatus due to the pandemic.
As huge crowds gathered on Sunday, two people were injured when a bus shelter collapsed in the Ladbroke Grove area.
Several people were seen standing and dancing on top of it before the incident, with those watching heard to gasp and exclaim in shock as the group fell through the top of the shelter.
The two people affected suffered minor injuries and did not need further treatment, police said.