Police in the US state of Texas have admitted that a video showing an officer fatally shooting a black 15-year-old shortly after leaving a party contradicts the department's original account of the incident.

Jonathan Haber, Balch Springs police chief, said on Monday that Jordan Edwards' vehicle was driving away from officers when he was killed on Saturday night in a suburb of Dallas.

That contradicted the account of events provided by the police a day earlier, which posited that Edwards, who was a popular football player with high marks in school, was reversing towards the police in an "aggressive manner".

On Monday, however, Haber said he was troubled by what he saw in the video but wouldn't release details other than to acknowledge he erred in describing the encounter.

An attorney for Edwards' family told the Associated Press news agency that the shooting brings to mind the high-profile deaths of other black people after police encounters that have sparked outrage and protest in recent years. He said that this case stood out for its "sheer recklessness".

According to the Guardian newspaper's The Counted database, at least 1,092 people were killed by police in the US in 2016.

Of that total, nearly a quarter were African Americans, although the group only accounts for roughly 12 percent of the total US population.

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Civil rights campaigners and activists say the disproportionate number of black Americans killed by police is part of a broader pattern of racial discrimination in the country's justice system.

"Black men are six times as likely to be incarcerated as white men, and Hispanic men are more than twice as likely to be jailed as non-Hispanic white men," says a fact sheet published by The Sentencing Project.

It added that people of colour make up around 67 percent of the 2.2 million people in the country's prisons and jails.

These disparities, particularly the killing of African Americans by police, has prompted the rise of the Black Lives Matter movement, a popular civil rights movement aimed at ending police violence and dismantling structural racism.