MPs and peers held a minute’s silence in memory of George Floyd, the black man whose death in US police custody has sparked a global wave of protests.
The House of Commons and Lords chambers, as well as virtual committee hearings, fell silent at 11am on Tuesday.
Since Mr Floyd’s killing on 25 May, protests have been held across the UK.
The prime minister has urged people to “work peacefully, lawfully” to defeat racism and discrimination.
Ministers were in Downing Street for their regular cabinet meeting as the silence was marked in parliament.
The prime minister’s official spokesman said the cabinet began by discussing the “anger and the grief that is not just felt in the US but around the world including the UK following the death of George Floyd”.
Writing on Twitter the Labour party leader Sir Keir Starmer said George Floyd “must not become just another name. His death must be a catalyst for change”.
On Monday, Home Secretary Priti Patel told MPs that, while most demonstrators acted peacefully, “justice will follow” for any who engaged in violence.
Mr Floyd died after a Minneapolis police officer kneeled on his neck for over eight minutes.