One person died on Monday from injuries sustained in the Friday attack on Coptic Christians in the Upper Egyptian Minya governorate, raising the death toll to 30 people and making it the deadliest attack on Egyptian Christians in recent history.
Boula Jorji died from his injuries at a Cairo hospital, state news agency MENA reported.
The death toll from the Minya attack has exceeded the 29 deaths from the April suicide bombing at a church in the Nile Delta city of Tanta.
On Friday, gunmen driving three 4x4 trucks "fired randomly" at a bus carrying Coptic Christians in Egypt’s Minya governorate.
At least 21 people were injured in the attack.
The militant group Daesh claimed responsibility for the attack on Saturday.
In response to the Minya attack, the Egyptian air force has carried out intensive strikes on "terrorist bases" in Libya, which authorities say were involved in planning and executing the attack.
On 9 April, the same day of the Tanta bombing, a suicide bomber attacked St Mark's Cathedral in Alexandria, killing 18 people.
Daesh also claimed responsibility for the attacks on the two churches.
Cairo imposed a nationwide three-month state of emergency after the April attacks.