"I'd also say, be very careful of those kids in the neighbourhood and don't get involved with them because, son, there's a 99 per cent chance they're going to kill you, not the police.
"And we've got to hear that from the black community. And what we've got to hear from the black community is how and what they are doing among themselves about the crime problem in the black community."
Giuliani's comments come after the slaying of five police officers in Dallas, as well as the recent incidents in Minnesota and Louisiana in which black men were shot dead by police, sparking national outrage.
US authorities yesterday arrested more than 200 people as unrest continued after the recent shootings. Among those arrested was DeRay Mckesson, a well-known activist in the Black Lives Matter movement. He was released earlier today.
There were 990 people shot dead by US police in 2015, according to a Washington Post database, and there have been more than 500 fatal police shootings so far in 2016, the database shows.
On Twitter, Giuliani's comments were blasted by critics:
Giuliani also decried the name of the "Black Lives Matter" movement, calling it "inherently racist."
"Black lives matter. White lives matter. Asian lives matter. Hispanic lives matter," he said. "That's anti-American, and it's racist."
The statements echoed previous comments Giuliani made on MSNBC, which were also met with criticism.
