De Blasio made the comments after the fatal shootings of three people at Jewish-affiliated facilities near Kansas City Sunday. The alleged gunman has been arrested.
In a statement, the mayor also offered condolences and prayers for the victims, their families and the entire Jewish community.
Earlier this month, police officials said there was no credible terrorist threat detected in New York City ahead of the Jewish holiday.
Passover is one of the most widely celebrated Jewish holidays. It began Monday at sundown