Extremist group ISIS is targeting participants at the Halifax International Security Forum through social media.

In a statement, the president of the forum says ISIS is using the forum’s hashtag, HISF2014, to circulate video featuring a British captive.

Peter Van Praagh says ISIS is also sending private messages to participants and staff at the event.

He adds ISIS must, “feel intimidated by the openness and transparency of our forum,” and says he is not surprised.

Organizers say they are monitoring the situation.