Prime Minister Sir Keir Starmer said people were rightly sickened by the horrific attack on Monday night in north Belfast.
“But let me be clear, the acts of violence and arson that followed are totally unjustified,” he added.
The prime minister said he had spoken to Northern Ireland’s first and deputy first ministers, and the PSNI chief constable.
“We are united in calling for calm and determined to restore order, support the police and all those on the front line, and ensure that justice is done,” he added.
Conservative leader Kemi Badenoch said the scenes were “deeply disturbing”, adding that people had a “right to be angry” and the right to “expect politicians to secure our borders”.
“But no-one has a right to burn families out of their homes or to burn public property and attack the police,” she added.