Tens of thousands of demonstrators have taken to the streets of cities across the US, including Washington and New York, to protest against the killings of unarmed black men by police and call on politicians to act.
Organisers expect the rallies to be among the largest seen over the lethal actions of officers in New York, Cleveland and Ferguson, Missouri.
Protesters in Washington carried placards reading "Black Lives Matter" and "Who do you protect? Who do you serve".
Among those taking part in the march on the US Capitol Building - the seat of the US Congress - are the families of Eric Garner, killed by an officer using a chokehold position in New York, Michael Brown, who was fatally shot in Ferguson, Trayvon Martin, who was shot by a neighbourhood watch volunteer in Florida, and Tamir Rice, who was fatally shot in Cleveland last month.
Esaw Garner, the widow of the 43-year-old who died in July after officers arrested him in Staten Island on suspicion of selling loose, untaxed cigarettes, told marchers: "Let's keep it strong, long and meaningful."
The lack of criminal charges brought by grand juries in the New York and Ferguson cases have fuelled protests around the US.
'We need more than talk'
Civil rights leader the Rev Al Sharpton, whose National Action Alliance is heading the Washington protest, said in a statement: "We need more than just talk - we need legislative action that will shift things both on the books and in the streets."
He called for legislation that would allow federal prosecutors to take over cases involving police.
Local prosecutors who work with police regularly and then must investigate officers faced a conflict of interest, he argued.
The Washington protest will include the families of Eric Garner and Akai Gurley, who were killed by police in New York; Trayvon Martin, shot dead by a Florida neighbourhood watchman in 2012; and Michael Brown, killed by an officer in Ferguson.
Protesters are expected to arrive by bus from as far away as Florida, Connecticut and Pittsburgh.
The rally is set to block Pennsylvania Avenue between the White House and the US Capitol.
The march in New York, a city which has seen a series of protests after a grand jury failed to indict the officer who killed Mr Garner using a chokehold, is expected to draw 44,000 people.
New York march co-organiser Umaara Elliott said in a statement: "It's open season on black people now.
"So we demand that action be taken at every level of government to ensure that these racist killings by the police cease."
Protesters have been tweeting throughout today's demonstrations:
There are a TON of people here. DC. #Ferguson pic.twitter.com/7Lag6LlLGA
— deray mckesson (@deray) December 13, 2014
Only in America. DC. #Ferguson pic.twitter.com/aF1hLcXWuK
— deray mckesson (@deray) December 13, 2014
Originally posted at 18.00
