Montreal's oldest Jewish day school was fire-bombed last week by a group which said it wanted revenge for Israel's assassination of Hamas co-founder Sheik Ahmed Yassin.
The blaze, started at 2:30am on April 5, left classrooms smoke-damaged and destroyed the library.
"Our goal was only to sound the alarm without causing deaths. This is just a beginning," reads part of a note found at the school that the police have refused to release. "If your crimes continue in the Middle East, our attacks will continue."
Pupil Mathew Cadoch, 12, said: "Even if all our books are gone, we will still be the same as before, the same Jews, the same people."
The attack followed a spate of anti-semitic incidents in Toronto that included overturning grave stones and painting swastikas on the doors of Jewish residents, which have worried Canadian Jews and drawn a strong reaction from politicians.
Justice minister Irwin Cotler, who attended a branch of the Talmud school, said that anti-Semitism was increasing both in Canada and worldwide.
"Canada will not be silent and we will not be intimidated. We will bring the full force of law to bear against those who would commit these cowardly acts of racist, hate crimes," he said.
Montreal mayor Gerald Tremblay promised an increased police presence at Jewish institutions during the holiday period.
Last month, B'nai Brith Canada reported an increase in anti-Semitic incidents across the country in 2003, saying there were almost 600 cases of violence, harassment and vandalism against Jews and over 100 such incidents in Quebec alone.