According to a report on غزة الان on Facebook, the IOF arrested Haj Abu Ghazi Sarhan, chairman of a Silwan-based Islamic charity in the pretext he is affiliated with Hamas. The Haj was arrested at a beginning of a planned community Iftar in Ras al-‘Amoud.
[We posted a live report about the raid here: https://intifadamedia.wordpress.com/2012/07/28/iof-raiding-ras-al-amoud-in-jerusalem-4/]
Update: Israeli police claims they disrupted a Hamas-sponsored conference and that they arrested two of its organizers. According to the police announcement, they discovered the existence of this event through informers and attained a formal police order to cease activity.