A man carries an Egyptian police officer to an ambulance after a blast at the Egyptian police headquarters in downtown Cairo, Friday, Jan. 24, 2014 (Photo: AP)
Egyptian police officers sit on the street after a blast at the Egyptian police headquarters in downtown Cairo, Friday, Jan. 24, 2014 (Photo: AP)
Egyptian police officers and firefighters gather at the Egyptian police headquarters after a blast in downtown Cairo on Friday, Jan. 24, 2014 (Photo: AP)
People surround a body covered with a blanket on the street after a car bomb explosion at the Egyptian police headquarters in downtown Cairo, Friday, Jan. 24, 2014 (Photo: AP)
Police officers and people gather in front of the damaged Cairo Security Directorate building, after a bomb blast occurred at the police headquarters nearby, in downtown Cairo, January 24, 2014 (Photo: Reuters)
Egyptian police officers walk thorough water that came out of the underground water pipe after a blast at the Egyptian police headquarters as firefighters check the damage in downtown Cairo, Friday, Jan. 24, 2014 (Photo: AP)
Police officers and people gather in front of the damaged Cairo Security Directorate, which includes police and state security, after a bomb attack in downtown Cairo, January 24, 2014 (Photo: Reuters)
Police officers and people gather in front of the damaged Museum of Islamic Art building, after a bomb blast occurred at the nearby Cairo Security Directorate, which includes police and state security, in downtown Cairo, January 24, 2014 (Photo: Reuters)
Police officers stand guard in front of the damaged Cairo Security Directorate, which includes police and state security, after a bomb attack in downtown Cairo, January 24, 2014 (Photo: Reuters)
An injured police officer is assisted by people out of the damaged Cairo Security Directorate, which includes police and state security, after a bomb attack in downtown Cairo January 24, 2014 (Photo: Reuters)
Protesters supporting the Egyptian army and police shout slogans against the Muslim Brotherhood in front of the damaged Cairo Security Directorate, which includes police and state security, after a bomb attack in downtown Cairo, January 24, 2014 (Photo: Reuters)
Egyptian police officers stand guard at the site of a blast at the Egyptian police headquarters in downtown Cairo, Egypt, Friday, Jan. 24, 2014 (Photo: AP)
An Egyptian firefighter checks a crater made due to a blast at the Egyptian police headquarters in downtown #Cairo, #Egypt, Friday, Jan. 24, 2014 (Photo: AP)
An Egyptian man stands in rubble after an explosion at the Egyptian police headquarters in downtown Cairo, Friday, Jan. 24, 2014 (Photo: AP)
A riot police officer reacts as he squats in front of the damaged Cairo Security Directorate building, which includes police and state security, after a bomb attack in downtown Cairo, January 24, 2014 (Photo: Reuters)