Egyptian prosecutors announced on Tuesday that a number of defendants accused of involvement in three recent deadly church suicide bombings in Egypt have confessed to the crime, state news agency MENA reported.

According to the confessions, the defendants participated in a 2013 sit-in in Cairo's Rabaa El-Adaweya protesting the ouster of Islamist president Mohamed Morsi earlier that year, and also received military training in Libya with Al-Qaeda and the Islamic State militant group.

The defendants are accused of involvement in the December 2016 suicide bombing of St Peter's Church in Cairo, which killed 29 worshippers, as well as the two Palm Sunday suicide bombings in April 2017 that killed 46 people at two Coptic churches in Tanta and Alexandria.

On Sunday, Egypt's general prosecution referred 48 defendants to military court on charges of involvement in the three church bombings, according to a statement by Prosecutor-General Nabil Sadek.

The defendants are also charged with being members of terrorist cells affiliation with the Islamic State group, and manufacturing weapons and explosives, among other charges, according to the statement.

The Palm Sunday bombings, which were claimed by the Islamic State militant group, were the deadliest attacks on Copts in the country's recent history.

A three-month state of emergency was declared on the day of the church attacks.

In December 2013, an Egyptian court designated the Muslim Brotherhood a terrorist organisation after the government blamed the group for a number of deadly attacks on security forces and civilian targets, including churches, in the aftermath of Morsi's ouster. 

Authorities have since repeatedly accused the Brotherhood of links to the militant violence.

Egypt's security forces have been battling a decade-long militant Islamist insurgency centred in North Sinai, which intensified since the ouster of Morsi.