Netizens and journalists are reporting that thousands of Muslim Brotherhood members and supporters are heading towards the National Security building in Nasr City now.

Muslim Brotherhood supporters surround the National Security headquarters in Nasr City, Cairo. Photograph shared by @amrsalama on Twitter
Amr Salama El-qazaz shares this photograph.
آلاف المتظاهرين يحاصرون مقر مباحث أمن الدولة الآن بمدينة نصر #رابعة_العدوية pic.twitter.com/oxBFRmzYrN
@amrsalama: Thousands of protesters are surrounding the National Security headquarters in Nasr City now