New York City police will be increasing security at synagogues and Jewish community centers during the Passover holiday, which begins Friday evening.

Authorities say heightened security is not due to a specific threat but is part of the city's post 9/11 efforts to fight terrorism. 

Experts say terrorists could attack Jewish groups outside of Israel, such as the deadly attack at the Ozar Hatorah school in Toulouse, France, last month, where three children and a rabbi were shot dead.

Following the school attack, NYPD dispatched extra patrols to more than 50 Jewish sites in Manhattan.

"We'll ensure that coverage is more than adequate in those neighborhoods, adding foot posts, visits by officers to synagogues, outreach by community affairs officers and a heightened presence of anti-crime," Police Commissioner Raymond Kelly told Jewish community leaders Tuesday.