TORONTO -- At least eight synagogues in four cities across Canada have received anti-Semitic letters calling for the death of Jews, B'nai Brith Canada said.

Four synagogues in Toronto, two in Montreal, one in Hamilton and one in Edmonton have reported being sent the hate mail, the Jewish advocacy group said Tuesday.

A photo on B'nai Brith Canada's website shows the letter containing the words "Jewry must perish," and a swastika scrawled onto a blood-soaked Star of David.

"It's really unfortunate that, at this time of year, with the Jewish community celebrating Hanukkah ... you have a message of targeted hate that's going out to religious institutions across the country," B'nai Brith Canada CEO Michael Mostyn said. "It's sad to see and it's actually quite terrifying for the individuals opening these letters with hateful genocidal messages."

Police in all four cities confirmed they were investigating the letters.

Officers are "absolutely" treating the incidents as hate crimes, said Staff Sgt. Frank Partridge of 32 Division in north Toronto, where one of the targeted synagogues is located.

"This is something that's happening in real time -- today, yesterday -- it's happening in (other cities) so there's a linkage there," Partridge said.

"Starting tomorrow, I'm having my officers go out and pay special attention to the synagogues and other Jewish facilities... You've got to be proactive about this."

There were 1,728 anti-Semitic incidents reported throughout the country in 2016, according to B'nai Brith's statistics. That's a 26 per cent increase from 2015 and the highest number of incidents ever seen by the organization, which has been tracking anti-Semitism for 35 years.

B'nai Brith does not yet have anti-Semitism statistics for 2017.

Police across the country received more reports of hate crimes against Jews, than they did any other religious, ethnic or racial group in 2016, according to Statistics Canada data.

"Unfortunately some (people) feel emboldened at this moment in history to express hate toward identifiable groups and Jews in particular," Mostyn said, pointing to the high-profile neo-Nazi rallies in Charlottesville, Va., earlier this year, and a series of anti-Semitic posters put up on university campuses in Canada.