Four suspects in a Cairo church bombing which killed 25 people have been referred to state security prosecutors for a remand hearing, officials said on Tuesday.

They will ask prosecutors to remand the four in custody for up to 15 days while the investigation continues.

One of the four, identified by the interior ministry as Rami Mohamed Abdel Hameed Abdel Ghani, is suspected of hiding the explosives and the bomber, and of preparing him for the attack.

The president named the bomber as Mahmoud Shafik Mohamed Mostafa, 22. The interior ministry said he was identified by DNA tests.

Egypt's Coptic Christian minority accounts for up to 10 percent of the population and has long complained of persecution and discrimination.

The church targeted in Sunday's bombing lies next to Saint Mark's Cathedral, the seat of Coptic Pope Tawadros II.

Police are searching for several other suspects.

The interior ministry named the suspected ringleader as Mohab Mostafa el-Sayed Qassem, also known as "The Doctor".

It charged he had travelled to Qatar in 2015 to meet fugitive leaders of the outlawed Muslim Brotherhood, the party of president Mohamed Morsi, who was ousted by Sisi in 2013.

The Brotherhood has condemned the bombing and denied any involvement.