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.
At least one person was killed and 10 injured, including three children, in overnight drone attacks by Russia on Ukraine, officials said on Wednesday. Various attacks also damaged energy facilities in two regions, according to the Ukrainian president Volodymyr Zelenskyy.
Israel announced a major expansion of military operations in Gaza on Wednesday, saying large areas of the enclave would be seized and added to its security zones, accompanied by large-scale evacuation of population.
A fourth US Army soldier, who together with three others went missing in Lithuania last week when their vehicle sank in a peat bog, has been found dead, US and Lithuanian officials said on Tuesday.
The United Nations on Tuesday dismissed as "ridiculous" an assertion by Israel that there was enough food in the Gaza Strip to last for a long period of time, despite the closure of all 25 bakeries supported by the World Food Programme (WFP).
United Nations officials who surveyed earthquake damage in Myanmar urged the global community to ramp up aid before the looming monsoon season worsens already catastrophic conditions, with the death toll at 2,719 and expected to surpass 3,000.