A hate-monger hurled anti-Semitic insults at a Jewish man on a busy Brooklyn street, police sources told The Post.

“Hail Hitler!” the anti-Semite shouted, throwing an unknown liquid at victim Joseph Singer, according to the sources.

“Hitler is coming to kill you Jews. He is going to burn you up.”

The hate-filled statements were made Sunday at about 1:50 p.m. at Grand and River streets in Williamsburg while Singer was cleaning his car, the sources said.

The attacker ran off after the verbal assault.

Police are investigating the confrontation as a bias incident.

Even though cops said he used the words “Hail Hitler,” sources believe he really meant, “Heil Hitler!” — the Nazi salute.

There were no physical injuries during the incident.