Police in the United States are more likely to disproportionately kill black people in communities where whites harbor more racial bias, according to a new study.

Racial attitudes in US communities play a role in police killings, according to a study by researchers at Ryerson University in Toronto, Canada.

The study found that implicit racial bias among whites was the only factor associated with police disproportionately killing African Americans.

The study was published Thursday by the journal Social Psychological and Personality Science.

In a lot of the media stories there's kind of this onus on the police - that they're responsible or that they're racist, and that's why these events are happening, lead author Eric Hehman.

I'm not saying that the police don't have these biases themselves. What I'm saying is it's not just the police that have these biases, Hehman said.

It's really just the attitudes of whites in an area that's driving to what extent blacks are killed by police, he added.

The study's researchers compared data of police killings from different regions of the US in 2015 with levels of racial prejudice in those communities.

Hehman said he'd like to do a similar study in Canada, but there's a lack of available police data. We'd expect this to be happening in Canada as well, absolutely, whether it's with blacks or First Nations.

A string of police killings of unarmed African Americans has led to the creation of the Black Lives Matter movement and raised nationwide debates about police violence.

US police officers fatally shot nearly 1,000 people last year, amounting to three deaths each day, according to an investigation by the Washington Post. A disproportionate number of those killed in 2016 were black, and about a quarter involved a victim who had a mental illness.

Numerous demonstrations have been held across the country in recent years following white police officers killing unarmed African-American men, including Michael Brown in Ferguson, Missouri; Tamir Rice in Cleveland, Ohio; Eric Garner in Staten Island, New York and Walter Scott in North Charleston, South Carolina.