Sometimes, nothing was said but there was a punch or slap out of nowhere. Other times, the assailant shouted a hateful slur that left no question of motive: “F- -k you, Jews!”

There have been eight attacks in the city so far this week, all during Hanukkah, that are being investigated as anti-Semitic hate crimes, police said on Friday — a spree of harassment and misdemeanor assaults that the NYPD chief of detectives called “alarming.”

All but one of the attacks happened in Orthodox Jewish neighborhoods in Brooklyn, including the most recent one, when a man barrelled into the Chabad-Lubavitch World Headquarters on the Eastern Parkway in Crown Heights just before 7 a.m. Friday.

The man shouted that he was going to shoot the place up, then ran out toward the Utica Avenue subway station, police and witnesses say.

“We will not accept it,” Mayor Bill de Blasio said at a press conference outside the building.

“We hear the pain and the fear that people in this community are feeling,” he said, promising a heightened police response in Borough Park, Crown Heights and Williamsburg, where the attacks have been concentrated.

“Anyone who commits a hate crime, we will find them, and we will prosecute them. No exceptions.”

Suspects had been arrested in three of the eight attacks as of Friday night.

All of the incidents have been assigned to the NYPD’s hate-crimes task force, said Chief of Detectives Rodney Harrison.

“We treat them very seriously, and we make sure that our investigators do their best … to bring the individuals to justice,” he said.

But at the Lubavitch headquarters, people were still skeptical.

“This is [de Blasio’s] playbook,” said Bryan Lieb, a board member of the New York-based Americans Against Anti-Semitism. “It’s press conference after press conference . . . Where’s the actual action?”

The attacks had local Jewish groups demanding more patrols at Orthodox sites and an all-out pursuit of the assailants.

“We call on NYPD to drastically increase police visibility in Orthodox communities,” the NYC Jewish Caucus tweeted.

Guardian Angels leader Curtis Sliwa said his group was asked by some Jewish Brooklyn residents to help protect the targeted neighborhoods. They will start patrols on Sunday, Sliwa said.

The spate of hate began at East 41st Street in Manhattan Monday morning, hours after the first night of Hanukkah.

Steven Jorge, 28, of Miami allegedly shouted, “F- -k you, Jew bastard!” as he punched and kicked a 65-year-old Jewish man who was wearing a yarmulke.

Early Tuesday, a group of people hurled anti-Semitic slurs at a 25-year-old Jewish man outside 332 Kingston Ave. in Crown Heights.

Later Tuesday, a 56-year-old Jewish man was punched from behind by a group of people on Union Street in Crown Heights.

Early Wednesday, a 40-year-old Jewish man was punched in the chin by a stranger.

On Thursday afternoon, Ayana Logan, 42, identified as homeless by police, allegedly approached a 34-year-old woman and her 3-year-old son on Avenue U in Gravesend yelling, “You f- -king Jew, the end is coming for you!” and hit the mom with her bag.

Early Friday at Eastern Parkway and Kingston Avenue, Tiffany Harris, 30, of Flatbush allegedly slapped three women in the face and barked, “F- -k you, Jews!” The victims, ages 22, 26 and 31, were not seriously injured.

Additional reporting by Jacob Henry and Laura Italiano