White cops and correction officers are being targeted for death by a black prison gang in what’s being called “Black August,” according to a chilling security bulletin obtained by The Post.

The bulletin was issued by the FBI’s National Gang intelligence Center, and the warnings were passed on to city Correction officials on Aug. 5.

“The warning involves an increased risk for violence during ‘Black August,’” say a sternly worded internal memo issued to commanding officers at city jails.

Two days after the warning, a city correction officer at Rikers was beaten up and slashed by an inmate, who also pummeled a second guard. That attack was not related to the Black August threat, a Correction Department spokeswoman told The Post.

But DOC officers are now on high alert, she said.

“Commanding officers are instructing all staff to be cognizant of their surroundings and extremely vigilant at all times,” the spokeswoman said. “As always we are regularly assessing threats and taking appropriate security measures.”

The FBI memo warns that members of the gang discussed ambushing officers who were parked in alleys or on side streets.

A prison gang known as the Black Guerrilla Family, a group tied to the Black Panthers, began Black August in the California penal system in the 1970s to honor fallen members, particularly Black Panther George Jackson, who was shot to death by prison guards at San Quentin when he tried to escape in 1971.

The gang, which still has members across the country, has called on inmates to kill correction officers and members of the Aryan Brotherhood.

The safety alert, citing an inmate source, “claims the BGF has a 2-for-1 kill policy. That the BGF is “going to kill correctional officers and Aryan Brotherhood gang members to send a firm message. And the attacks will occur across the country, not just in California.”

A city correction officer who was unaware of the alert said that “captains and deputies and wardens don’t always tell us what’s going on. If any officer gets hurt, we don’t always find out about it from our supervisor — even if it’s in our own facility. They’ll be like, ‘Do your job properly or make sure to follow procedures,’ but they won’t go into specifics.”

There were 394 inmate assaults on Correction staff for the first six months of 2016, according to a DOC spokeswoman. She could not say how many officers have been attacked in the first two weeks of August.