A police officer was shot dead on Sunday while trying to detain demonstrators in Istanbul's Gazi neighborhood, hospital sources said.Muhammet Fatih Sivri, a member of the riot police unit, sustained gunshot wounds to the chest after attempting to enter a building in the neighborhood.He had been taken to Gaziosmanpaşa Taksim Training and Research Hospital, where he died.The perpetrators of the attack are being sought, security sources have said.The attack comes as police in Istanbul have dispersed a group "belonging to an illegal organization" after they blocked a main street and attacked police officers with sticks, stones and Molotov cocktails, police said Sunday.The group, who were wearing uniforms and masks, was dispersed because it was taking advantage of the funeral ceremony of a woman -- reportedly a member of the outlawed far-left Revolutionary People's Liberation Party-Front (DHKP-C) -- who was killed in Bagcilar on Friday, Istanbul Police Department said in a written statement Sunday.The corpse of the woman, who lived in Tuzla district of the city's Asian side, was forcibly taken to a djemevi -- an Alevi place of worship -- in Gazi neighborhood in Sultangazi district on the European side.Police said it was propaganda for the leftist terror organization. The police department in Gazi neighborhood had taken some safety precautions to allow safe transfer of the corpse to the graveyard, police said, adding precautions were not against the rituals of the funeral.Istanbul Governor's Office, too, stressed in a statement on Sunday that the funeral ceremony would go ahead as normal, but security forces would not allow it to turn into terrorist propaganda.The woman was killed during a shootout with police in a wave of anti-terror operations across the country, which saw over 800 detentions on suspicion of having links to terrorist groups, including DAESH (An alternative arabic acronym for ISIS, the self-proclaimed Islamic State of Iraq and al-Sham terrorist organization) and the outlawed PKK.