At least 37 people were killed and more than 100 injured in two separate Palm Sunday bombing attacks at Coptic Christian churches in Egypt.
The first blast happened at a church in the Nile Delta town of Tanta, where at least 26 people were killed and 71 others wounded, officials said.
Television footage showed the inside of the church, where a large number of people gathered around what appeared to be lifeless, bloody bodies covered with papers.
A second attack was later reported in Alexandria, leaving at least 11 dead, and 35 injured.
No one immediately claimed responsibility for the attacks, which come a week before Christians worldwide will celebrate Easter.
"Either a bomb was planted or someone blew himself up," provincial governor Ahmad Deif told the state-run Nile TV channel, Sky News reported.
The attack in Tanta was the latest in a series of assaults on Egypt's Christian minority, which makes up around 10 percent of the population and has been repeatedly targeted by Islamic extremists.
The attacks came just weeks before Pope Francis is due to visit Egypt.
Grand Sheikh Ahmed el-Tayeb, head of Egypt's Al-Azhar — the leading center of learning in Sunni Islam — condemned the attack, calling it a "despicable terrorist bombing that targeted the lives of innocents."
A local Islamic State affiliate claimed a suicide bombing at a church in Cairo in December that killed around 30 people, mostly women, as well as a string of killings in the restive Sinai Peninsula that caused hundreds of Christians to flee to safer areas of the country. The group has threatened further attacks.
A militant group called Liwa al-Thawra claimed responsibility for an April 1 bomb attack targeting a police training center in Tanta, which wounded 16 people. The group, believed to be linked to the outlawed Muslim Brotherhood,has mainly targeted security forces and distanced itself from attacks on Christians.
Egypt has struggled to combat a wave of Islamic militancy since the 2013 military overthrow of an elected Islamist president.