The US Justice Department will launch a federal civil rights investigation into the choking death in New York of a black man at the hands of a white policeman, Attorney General Eric Holder has said.
The announcement came hours after a New York grand jury opted not to indict the police officer in the death of Eric Garner, sparking protests in the United States' largest city.
In the video Mr Garner can be heard saying "I can't breathe" as he is held on the ground by several police officers.
The officer at the centre of the case has said he became a police officer "to help and protect those who can't protect themselves.
"It is never my intention to harm anyone and I feel very bad about the death of Mr Garner", he said in a statement.
Attorney General Holder said he had spoken with Mr Garner's widow, President Barack Obama and New York City Mayor Bill de Blasio about his decision to launch an inquiry.
"Our prosecutors will conduct an independent, thorough, fair and expeditious investigation. In addition to performing our own investigative work, the department will conduct a complete review of the material gathered during the local investigation," he stressed.
"I know that substantial numbers of people in New York and across the country will be disappointed and frustrated by the outcome of the state grand jury proceeding today," Mr Holder said.
"I know many will plan to voice their disappointment publicly through protests. This is the right of all Americans.
"But as I have said before, throughout our history, the most successful movements have been those that adhered to the principles of nonviolence."
Mr Holder, the first African-American to hold the attorney general post, under the first black US president, was speaking as demonstrators took to the streets in New York City and Washington to protest the grand jury's move.
Gwen Garner, Eric Garner's mother, said she was "truly disappointed" in the grand jury's decision.
"I don't know what video they were looking at, evidently it wasn't the same one that the rest of the world was looking at", she said.
"How can we put our trust in the Justice System when they fail us like this. They are breaking my heart", Ms Garner said.
Mr Garner's widow, Esaw, said she is determined to get justice for her husband "because he should not have been killed in that way, he should not be killed in any way, he should be here celebrating Christmas and Thanksgiving and everything else with his children and grandchildren and he can't because a cop did wrong.
"Someone who gets paid to do right did wrong and he is not held accountable for it and my husband's death will not be in vain as long as I have breath in my body, I will keep fighting", she said.
