(CNN) - More than half the hate crimes reported in New York City so far this year are anti-Semitic, New York Police Department officials said on Wednesday.
The incidents reported are mostly acts of vandalism, with graffiti or swastikas being scrawled on places that include synagogues, according to New York City Chief of Detectives Dermot Shea. The latest numbers cover hate crimes reported through September 1.
"The vast majority do not involve personal action and assault," Shea said at a monthly crime statistics briefing, though he noted that the hate crime numbers included some reports of assaults.
And as a whole, anti-Semitic hate crimes in New York City are up 63% this year as compared with last year, officials said.
So far this year, there have been 152 reports of anti-Semitic hate crimes, while over the same period last year there were 93, according to NYPD statistics.
In all, there have been 290 reports of hate crimes this year as compared with 205 last year, statistics show.
NYPD officials also say arrests related to hate crimes are up. There have been 135 arrests so far this year as compared with 108 over the same period last year.
Despite the spike, Shea said there was no definitive cause for the increase, and, more specifically, the jump in reports of anti-Semitic incidents.
"A number of cases that I've highlighted, we've seen some mental illness," Shea said. "We've seen some people that just hate. So we've seen a little bit of everything."
While most of the reports have dealt with vandalism, the NYPD's Hate Crimes Task Force recently investigated the case of a 63-year-old Jewish man who was running in a Brooklyn park when he was assaulted with a brick by an unknown man on August 27, police said.
Shea also mentioned a string of attacks in Brooklyn where victims were attacked on their way to morning services.
Other incidents included the discovery of a Post-it note with the phrase "Hitler is Coming" written on it and placed on a billboard display in front of the Jewish Children's Museum in Brooklyn in June, police said.
Also in June, a man was caught on surveillance video scrawling an anti-Semitic phrase on the front door of a medical office in Harlem, police said.
And in May, a man was attacked in Brooklyn by a group who hurled anti-Semitic comments during the beating, police said.
In response to the hate crimes, NYPD officials have deployed auxiliary police officers to houses of worship, made sure community affairs officers were in touch with religious leaders and discussed crime prevention strategies, said NYPD Chief of Patrol Rodney Harrison.
"We'll continue to take a look at all the concerns throughout the city and make sure we address it accordingly," Harrison said.
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