Whites make up 60 per cent of the population but comprise 50 per cent of the deaths by police.
That means, 32 black people per million perish by police violence versus 13 white people per million, according to calculations based on The Washington Post numbers.

Barr's comments come as the US remains convulsed with racial unrest, most recently enflamed by the death of George Floyd, a black man, by Minneapolis police officers in May. The video of his death in custody helped trigger riots and protests across the US.

More recently, in Kenosha, Wisconsin, Jacob Blake, a black man, was shot seven times in the back by police as they tried to arrest him.

Barr also said on Wednesday that mail-in ballots for the November 3 election could be vulnerable to fraud, echoing an argument President Donald Trump has made to denounce the use of voting by mail.

"People trying to change the rules to this methodology, which, as a matter of logic, is very open to fraud and coercion. It's reckless and dangerous, and people are playing with fire," Barr said.

Voting by mail is not new in the United States - nearly 1 in 4 voters cast presidential ballots in 2016 that way. Experts say voter fraud of any kind is exceedingly rare in the United States.

Barr cited a 15-year-old report by the Commission on Federal Election Reform, chaired by former President Jimmy Carter and former Secretary of State James Baker, which concluded that absentee ballots are the largest source of potential voter fraud.

"Since that time, there have been in the newspapers, in networks, academic studies, saying it is open to fraud and coercion," Barr said. "The only time the narrative changed is after this administration came in."

He said there are a number of ongoing investigations into voter fraud, "some very big ones in states."

A record number of mail-in ballots are expected for the November 3 election due to concerns about in-person voting during the coronavirus pandemic.

Trump has accused Democrats of trying to steal the election by pushing the use of mail-in voting. Democrats have said Trump and fellow Republicans are attempting to suppress the vote to help their side.

Barr said arrangements could be made at polling stations to protect people from the coronavirus and that people with pre-existing conditions who are particularly vulnerable could get an absentee ballot.

He also raised the spectre of a foreign government counterfeiting US ballots, although he said he had seen no evidence of such an effort.

Barr said he believes China is more of a threat than Russia when it comes to interfering in the election. "I've seen intelligence. That's what I've concluded," he said, without offering details.

But Barr said there was "some preliminary activity that suggests" Russia might try to interfere again in the election. "It wouldn't surprise me if Russia tries something again," he said.

Former Special Counsel Robert Mueller concluded that Russia used a campaign of propaganda and hacking to boost Trump's candidacy in the 2016 election.

Barr also said the Justice Department was monitoring the anti-fascist protest movement Antifa, calling it the "ramrod" of violence and looting in US cities.

"I've talked to every police chief in every city where there has been major violence and they all have identified Antifa as the ramrod for the violence," Barr said. "They are flying around the country. We know people who are flying around the country."

"We see some of the purchases they are making before the riots of weapons to use in those riots," Barr added. "So, we are following them."

Barr also said he thought there was a "false narrative" in the US that many unarmed Black people are being killed by white police officers.

Reuters with staff reporters