A series of measures have been announced by NYC Mayor Bill de Blasio to tackle a “crisis” of anti-Semitic attacks, following a mass stabbing on December 28.

A man brandishing a machete attacked a Hanukkah celebration at the rabbi’s property in Monsey, north of NYC – an area with a large population of ultra-Orthodox Jews. The incident happened at about 22:00 on December 28.

The mayor said security would be stepped up in Jewish areas and schools would teach students to tackle hate.

At least five people were injured in the knife attack at a rabbi’s house in Monsey.

President Donald Trump called for unity to fight “the evil scourge” of anti-Semitism following the attack.

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Witnesses said the attacker burst into the house, which was hosting a Hanukkah celebration, pulled out a large knife and began stabbing people.

The suspected knifeman, named by police as 37-year-old Grafton Thomas from Greenwood Lake, NY, has been charged with attempted murder. The attacker pleaded not guilty, and is being held in jail with his bail set at $5 million.

Grafton Thomas’ lawyer, Michael Sussman, issued a statement on behalf of his family which said the suspect “has a long history of mental illness and hospitalizations”.

The statement said: “He has no history of like violent acts and no convictions for any crime.

“He has no known history of anti-Semitism and was raised in a home which embraced and respected all religions and races. He is not a member of any hate groups.”

Just a day before the attack, Mayor de Blasio had announced extra police patrols in three areas of Brooklyn with large Jewish populations following a spate of anti-Semitic incidents.

He told reporters on December 29: “The spirit we bring today is one of resolve and relentlessness. We will keep adding as many measures as it takes to end this crisis.”

Bill de Blasio said additional officers would now be deployed to the districts of Williamsburg, Crown Heights and Borough Park.

He said: “People in the community will see our officers present in front of houses of worship and out on the streets. We have to give people a sense of security, and we have to show that this horrible trend we’ve seen over the last weeks will be stopped dead in its tracks.”

The mayor said changes would be made to the curriculum at schools in Brooklyn starting from next month. He said they would focus on “stopping hate… on building mutual respect, to help young people understand what hate crimes really mean and the dangers they pose to all of us”.