Fireworks and bottles have been hurled at riot police and mattresses set on fire in a protest over the death of Rashan Charles.
The 20-year-old died after being chased by police in east London on 22 July.
He then tried to swallow an object but died later in hospital, the Met Police said.
Protesters gathered in Kingsland Road, Hackney, with some holding Black Lives Matter placards, before violence broke out about 20:00 BST.
The force said it was continuing to monitor the situation but the mood was said to be “calming down” at about 22:30.
Earlier, police in Hackney tweeted: “Officers have been subjected to abuse and violence. Whatever the frustrations, this is patently not what the family of Rashan Charles wanted.”
The planned protest began on Friday at about 15:40.
By 20:00, dozens of people, some masked, were still lining the streets and shattered glass littered the road.
Bins, mattresses and debris were used to block the street and at one stage a lorry drove through the barricade with people clinging to it.
Bottles and fireworks were launched at riot police as they moved towards the crowd at about 22:00.
Videos on social media show officers walking backwards as objects are thrown at them.
Several wheelie bins were set alight and mattresses thrown on top of the burning pile.
Shop windows were also smashed, with those involved described by an eyewitness as “very, very angry”.
Pedestrians, motorcyclists and cyclists were told not to travel through the barricade.
The Independent Police Complaints Commission, which is investigating the events that led to Mr Charles’s death, said “we understand the concerns raised following Rashan’s death.”
A statement added: “We will independently examine the circumstances of this incident, we will follow the evidence, we will consider whether there is an indication there may have been misconduct or criminality, and we will seek to answer the questions that Rashan’s family and the community of Hackney understandably have.”