At least 21 people were killed when a bombing struck a church in northern Egypt on Sunday morning, according to the country's health ministry.
The explosion was reported inside the St. George church in the Nile Delta city of Tanta early Sunday.
"Twenty-one were killed and 59 others injured in the blast," ministry spokesman Khaled Mujahed said in a statement.
It remains unclear whether the blast was caused by a bomb or a suicide bombing.
No group has yet claimed responsibility for the bombing.
Sunday's bombing occurred on Palm Day, a Christian feast commemorating the entry of Jesus Christ into Jerusalem.
In December, a bomb blast struck a church in central Cairo, killing more than 25 people and injured scores.
Coptic Christians are estimated to account for between 8 and 10 per cent of Egypt's population of about 90 million.