Disturbing footage shows the moment a police officer collided with a traffic light, causing her to fall off a horse during a protest.
The horse then bolted and fled, reportedly hitting a Black Lives Matter demonstrator at Whitehall, London.
The distressing incidents happened as emotions became heightened with people gathered to show solidarity with George Floyd.
One shocking image shows a police officer laying flat on the ground, while other pictures appear to show the horses agitated by the swarms of people gathered.
The Met Police this evening said the officer was being treated in hospital for non-life threatening injuries, and that the horse was uninjured.
They tweeted: "The officer is currently in hospital, receiving treatment for her injuries which are not life threatening. The officer fell from her horse, and we are examining the full circumstances of what took place.
"The horse, uninjured, made its own way back to the stables, nearby."
Describing the clashes between officers and protesters earlier this evening, Mark White, Sky News Home Affairs correspondent, speaking from the scene described how there had been "a very serious escalation of disorder" in Whitehall, outside Downing Street.
He said: "The Metropolitan Police have just brought in mounted officers who just mounted a charge down Whitehall from the war memorial down to the cenotaph.
"You can see one of the officers has been knocked off his horse, that horse has now bolted.
"There are bottles and other objects being thrown at the mounted officers.
"In Downing Street, the other police officers who were guarding the gates in front of Downing Street have gone into full riot kit and have brought their riot shields out as well."
Videos circulating on social media appear to show missiles being thrown at officers in protective gear.
A bicycle was also reportedly thrown towards a police horse.
According to the Daily Mail, red flares were thrown over security gates at Downing Street.
Police in helmets and holding shields formed two lines outside of Downing Street, with mounted officers in-between to separate the crowds.
Some protesters linked arms and turned their backs to police to stop themselves being moved on.
A few demonstrators stood on walls outside of the Cabinet Office, holding signs and chanting.
Missiles were said to be launched at officers for around ten minutes, including fireworks and bangers.
Graffiti was also daubed on buildings on Whitehall, including the Cabinet Office.
A small "BLM" motif has been painted on the Cenotaph in black paint, while cardboard placards have been propped up on the war memorial's steps.