The Guardian Angels, a volunteer, unarmed group focused on crime prevention, will begin patrolling parts of New York with Jewish communities following a string of antisemitic attacks in the city.

Guardian Angels will begin patrolling Brooklyn’s Crown Heights neighborhood at noon and then move on to Williamsburg and Borough Park, the group’s founder, Curtis Sliwa, said.

“These attacks are taking place, and the cops have not been proactive at all,” Sliwa added. “It comes from City Hall and the mayor. He’s been just apathetic.”

The announcement comes after a machete-wielding man stabbed five Jews during a Hanukkah celebration at a rabbi’s home in Monsey, New York, on Saturday evening. The incident, described as “domestic terrorism” by New York Gov. Andrew Cuomo (D), comes as the New York Police Department (NYPD) is investigating eight antisemitic attacks in Brooklyn since December 13.

In the wake of the attacks, New York City Mayor Bill de Blasio has pledged to boost police presence in Jewish neighborhoods.

Besides making officers more visible in Borough Park, Crown Heights, and Williamsburg, police will boost visits to houses of worship and some other places, the mayor tweeted.

“I feel pained that in this society, a place that is supposed to be of respect for everybody, a season when we’re supposed to be respecting everybody, we see hate rearing its very ugly head. We will not accept it,” the Democrat said during a visit later Friday to Crown Heights, where he met with some representatives of the local Jewish community.

The attacks have happened as Jewish communities in the New York City metro area were already on edge after a deadly December 10 shooting rampage at a northern New Jersey kosher market. New Jersey Attorney General Gurbir Grewal said the attack was driven by hatred of Jews and law enforcement.

Another incident happened around 12:40 a.m. Friday, when a woman slapped three other women in the face and head after encountering them on a Crown Heights corner, police said. The victims, who range in age from 22 to 31, suffered minor pain, police said. Tiffany Harris, 30, was arrested on a hate-crime harassment charge. She was awaiting arraignment Friday. It wasn’t clear whether she had a lawyer who could comment on the charges, and no working telephone numbers for Harris could immediately be found.

The Associated Press contributed to this report.