Violence erupted for a seventh night across several parts of the US, just hours after President Donald Trump vowed to use military personnel to halt the protests.
"Mayors and governors must establish an overwhelming law enforcement presence until the violence has been quelled," Trump said.
"If a city or state refuses to take the actions that are necessary to defend the life and property of their residents, then I will deploy the United States military and quickly solve the problem for them."
Following his address, he walked from the White House to nearby St. John's Episcopal Church amid tight security to pose for pictures with his daughter Ivanka.
However, a few hours later, thousands of people marched through the streets of Brooklyn, shouting "justice now!", while demonstrators in Los Angeles and New York City clashed with riot police.
George Floyd, a 46-year-old African-American, was killed minutes after a policeman pinned his neck under a knee for nearly nine minutes.
The death toll from Nepal's devastating floods surpassed 1,000 on Tuesday as rescuers deployed heavy machinery, helicopters and excavators to reach thousands still missing nearly a week after the Himalayan disaster tore through towns and valleys.
Keir Starmer will stand down as a member of parliament, he said on Tuesday, some six weeks after he resigned as Britain's prime minister having lost the support of his Labour Party.
The German government said on Tuesday it had concluded that Russia was responsible for an attempted drone attack at Leipzig/Halle airport last month and ordered a series of measures in response, including the closure of a consulate and a Russian cultural centre in Berlin.
Novartis said on Tuesday it paused eight clinical trials of an experimental cell therapy, called rap-cel, targeting autoimmune and neurological disorders in late August, after three patients died.