“Terrified” bystanders spoke of the moment “a gang of screaming youths” descended on a street in east London.
One witness, who asked not to be named, described “around 200” people “screaming” in the street.
The Balls Pond Road resident told the Standard: “I was leaving my house and I heard a lot of sirens.
“As I walked up Balls Pond Road I saw around 200 people gathered outside of the shops, they were mainly girls and were screaming.
“It was terrifying. One of them smashed a bottle against a bin and they all ran.
“I was walking on the other side of the road and people there started running away too.”
Others took to social media to discuss the situation.
One user wrote: “What's going on in #Dalston?”
Another described hearing “loads of sirens”.
A Met Police spokeswoman said officers were unable to locate a disturbance while Hackney Police wrote on Twitter that they were monitoring the situation.
A statement read: “We deployed units & group were also monitored on CCTV. Sometimes our presence can inflame situations so we move away.”