In a historic moment, Pope Francis met the grand imam of Cairo's Al-Azhar Mosque at the Vatican.
Zawahiri served three years as a surgeon in the Egyptian Army, but his journey from an eye surgeon to becoming a most wanted global terrorist started after he met Laden in 1986, and joined Laden as his personal advisor and physician.
Thousands of defiant supporters of deposed Egyptian president Mohammed Morsi on Sunday staged a sit-in at Cairo, a day after the Muslim Brotherhood claimed that security forces killed nearly 200 Islamists, opening a deadly new phase of conflict in the deeply polarised country.