Cambridge cops are investigating after a President Trump supporter said he was savagely attacked after intentionally disrupting a book event featuring a prominent pro-antifa author near the Harvard campus.

The man, whose name was not released by police, told authorities he and some of his friends went to a book event Friday night hosted by the Harvard Coop — the bookstore affiliated with the school — featuring an address from Dartmouth lecturer Mark Bray, who has gained notoriety for suggesting there are times when it’s ethically acceptable to use violence against Nazi sympathizers and white supremacists.

Police said the victim told officers responding to the scene he was attacked shortly after the event let out.

“(The victim) stated he was punched in the face by the female and he tried to protect himself. At this time he stated other members of the group also began to punch him,” police said in a statement. “(He) was unable to provide a detailed description of any member of the group that assaulted him. He stated that there were 2 females and some males but he could not tell if any of the males assaulted him.”

Sohan Dsouza, who was at the event, said the victim and a few people he came with were trying to provoke participants by expressing support for Trump.

“There was a guy who was saying, ‘build the wall,’ ” he said. “They were provoking, kind of trolling everyone, trying to start provoking us all.”

Eventually, the group disrupting the event was escorted out of the bookstore. But on their way out, Dsouza said, someone took a parting shot.

“Someone threw a book at the back of his head as he was walking out,” he said.

The Harvard Coop declined to comment yesterday. A representative for Bray didn’t respond to repeated requests for comment.

In a video posted to social media, a man who identified himself as the victim, with extensive facial injuries, recounted the attack.

“We went to the talk. I felt like we were pretty good, we didn’t heckle too much, we were having a good time,” the man said from a hospital bed. “This group of people came out. This girl comes by, she said ‘this guy’s a Nazi,’ and before I could even respond verbally, another girl from that group, some short girl, started throwing fists at me.”

Although the victim said he was able to get free, he admitted to running back at them in an attempt to even the score.

“I was pretty pissed off at this point. I was like, these people aren’t going to hit me and hurt me without me getting something in there, so I went back after them again,” he said. “They came back after me, circled me again. The guy who hit hard hit me three or four times in the face. I was bleeding everywhere.”

The incident remains under investigation, Cambridge police said.