The discovery comes amid a series of missionary incidents reported recently in the vicinity of 770, prompting the shul’s administrator, Rabbi Yosef Yitzchok Kratz, to issue an urgent warning to the public.

Rabbi Yosef Yitzchok Kratz called on mispallelim to remain vigilant when opening siddurim and other seforim, and asked that whenever foreign material is discovered inside a siddur or sefer, it should be torn up and immediately discarded.

The latest incident follows other attempts by missionary groups to operate in the vicinity of the Chabad World Headquarters. Less than two weeks ago, a group of missionaries entered 770 wearing Christian symbols and asked to put on tefillin while recording the incident on video.

Meanwhile, in recent weeks there has been a continued presence of missionary groups outside the 770 building, including singing, livestreams, and attempts to distribute provocative material.

Rabbi Yosef Yitzchok Kretz clarified that, in accordance with the instructions of the Rabbanim, these individuals should not be permitted to put on tefillin, in order to prevent deception and the use of the mitzvah for missionary purposes.

The 770 administration is asking the public to remain vigilant, particularly regarding material found inside siddurim and other seforim, and to report any foreign or suspicious material that is discovered.