Egyptian President Abdel Fattah al-Sisi ordered military deployments to protect "vital and important infrastructure" after Daesh bombings hit two churches on Sunday, killing dozens of people.

"President Sisi... has decided to order the military to deploy protection units to guard vital and important infrastructure in all the republic's provinces," a statement from the presidency said.

Daesh claimed responsibility for bombing two Egyptian churches as worshippers gathered to mark Palm Sunday, killing at least 43 people in the deadliest attacks on the Coptic Christian minority in recent memory.

The attacks followed a Cairo church bombing in December and came weeks before a planned visit by Catholic Pope Francis intended to show support for Egypt's Christian minority.

The first bombing struck the Mar Girgis church in the city of Tanta north of Cairo, killing 27 people, the health ministry said.