A 20-year-old man hurled anti-Semitic insults at an elderly stranger, punching him in the face as he tried to enter a Brooklyn synagogue Monday night, police said.

The hate-fueled attack started around 9:30 p.m. in front of Congregation Kerem Shlomo on East 27th Street in Sheepshead Bay when the unhinged younger man suddenly socked the 67-year-old in the face and yelled anti-Semitic slurs, cops said.

“F—–g Jews!” he yelled, according to police sources. “I’m going to f–k you up. I see you Jews are racist.”

The alleged attacker, Hersham Ghonim, was arrested and charged with assault, assault as a hate crime, aggravated harassment, resisting arrest, criminal mischief and menacing, cops said. He was identified by police as black.

The NYPD Hate Crime Task Force was investigating, cops said.

The attack comes amid a rise in anti-Semitic incidents amid the Israeli-Palestinian conflict.