A 13-year-old girl has been arrested on suspicion of assaulting a police officer at a "yellow vests" protest in support of Brexit.
The teenager was among four arrested as demonstrators took to London's Westminster Bridge on Saturday.
Protesters donned yellow hi-vis jackets, emulating the "gilets jaunes" demonstrations that originated in France.
Scotland Yard said: "Four arrests have been made following protests on Westminster Bridge, SW1 at approximately 11am today.
"Three men arrested on suspicion of public order offences. A 13-year-old girl was also arrested on suspicion of assault on police. Inquiries continue."
Demonstrators were seen burning an EU flag while chanting: "Stick your flag with stars on up your arse."
Others sang: "We want Brexit. When do we want it? Now."
Smoke bombs were also seen strewn across Westminster.