The bombings at separate churches targeting Palm Sunday worshipers have been claimed by Islamic State
Egypt's president Abdel Fattah el-Sisi is expected to declare a three-month state of emergency.
It follows two bomb attacks on Coptic Christian churches in the country this morning, which killed at least 44 people.
Islamic State has claimed responsibility for the explosions in Tanta and Alexandria.
The first explosion, in Tanta - about 70 miles north of Cairo, killed at least 26 at the Mar Girgis Coptic Church.
Officials said the blast happened "in the front rows, near the altar, during the mass" and that more than 100 had been injured.
Video and pictures show crowds gathered around bodies and large blood stains on the pews and church walls..
Pope Tawadros II, head of the Coptic church, had earlier attended mass there.
"Either a bomb was planted or someone blew himself up," provincial governor Ahmad Deif told Nile TV of the Tanta blast.
A witness told the Reuters news agency: "There was a huge explosion in the hall. Fire and smoke filled the room and the injuries were extremely severe.
"I saw the intestines of those injured and legs severed entirely from their bodies."
Egypt is home to around nine million Coptic Christians and there have been previous attacks on them by groups linked to Islamic State.
The terrorist group also claimed responsibility for a bomb at a Cairo cathedral that killed at least 25 people in December 2016, many of them women and children.
Targeted killings in the country's Sinai peninsula also caused hundreds of Christians to flee the area in February, with an IS video urging more attacks.
Pope Francis, due to visit Egypt at the end of this month, condemned the attacks.
Egyptian state television said President Abdel Fattah al-Sisi had ordered an emergency defence council meeting.
Copts often suffer attacks in more rural areas of Egypt, usually over things such as the construction of a church or inter-faith relationships.
President Michael D. Higgins says his thoughts are with the people of Egypt and he's wishing the wounded a speedy recovery.