The NYPD has been on the alert for weeks for possible attacks similar to Friday’s deliberate RV explosion in Nashville, The Post has learned.

An internal NYPD memo issued earlier this month warned that law enforcement were the "priority targets" for terror attacks involving homemade bombs and vehicle arson.

The Dec. 14 memo, obtained by The Post, said violent extremists and "malicious criminal actors" might go after cops to exacerbate tensions, "exploit civil unrest" and incite further violence.  

LIVE UPDATES: NASHVILLE POLICE, FBI SEEK MOTIVE, A SUSPECT IN EXPLOSION

The document referenced Al-Qaeda propaganda released on Nov. 26 that urged  radical jihadists to exploit the COVID-19 pandemic to attack "priority targets."

Those targets included retired officers, business leaders, intelligence personnel and "soldiers and police of every brand."

Suggested attack methods were "stones, weights, edged weapons" — as well as improvised explosive devices and the arson of commercial buildings and vehicles.

Authorities haven’t yet released a motive for the attack in Nashville and no suspects have been identified, but retired NYPD detective Bill Ryan told Fox News he wouldn’t rule out first responders and police officers as the intended targets.

2 CHILDREN DIE IN CHRISTMAS MORNING FIRE IN DETROIT

"You have to really wonder what the motivation of the bombers are — I don’t think this was one person; it was probably an organized group of people," Ryan said.

Nashville cops responding to reports of "shots fired" in the city’s downtown area were drawn instead to the RV — which played a recording that said a bomb would go off within 15 minutes.

Officers were banging on doors and helping get residents to safety when the vehicle exploded, injuring three people.

"I kind of think it was probably an idea to get first responders to come in," said Ryan, who was part of an arson and explosions task force.

ARKANSAS FAR-LEFT JOURNALIST AMONG 4 CHARGED IN BLM FIREBOMBINGS OF POLICE VEHICLES: REPORT

"[They] give them a 15-minute warning and all the first responders, the police and the firemen come in," possibly making them prime targets of the bomb.

The NYPD memo said that a review of terrorism acts in the US this year highlighted the use of homemade bombs and incendiary devices, as well as vehicles, to strike law enforcement.

It included a graphic illustration of "recent neo-Nazi propaganda" showing a uniformed cop getting his throat sliced by a masked "ISIS-style executioner."

The doc also referenced the knife and gun attack on two NYPD officers near a June Black Lives Matter rally — allegedly by an ISIS-supporting Bosnian radical — to underscore the "real world threat" from online propaganda.

CLICK HERE TO GET THE FOX NEWS APP

The department assessed that those intent on attacking on and off-duty cops could take advantage of officers performing their regular duties and large-scale events to make a statement and quickly inflict damage.