The number of victims of the Alexandria church bombing reached 23 on Tuesday.
Church sources said Sabry Fawzy Wissa, one of the injured, died while undergoing treatment in hospital.
Protests have been staged across Egypt since Sunday following Saturday's church blast which claimed 22 lives and injured scores more. Protesters called on the government to provide Copts with greater security.
On Monday evening, thousands of Copts blocked main roads linking the capital with other cities, threw stones at cars and set tires ablaze. Similar protests took place in Cairo, Alexandria, Qalyoubiya and Assiut.
Police are currently imposing tighter security measures, especially near churches, as the eve of Coptic Christmas celebrations approaches on Thursday.
