Updated

An Egyptian military court on Thursday sentenced 17 Islamic militants to death for involvement in deadly attacks on Christians, a rights lawyer said.

The court in the Mediterranean city of Alexandria also issued life sentences to 19 defendants and sentenced another nine to 15 years in prison on terror-related charges, lawyer Khaled el-Masry said. Another defendant got a 10-year term, he said.

Military prosecutors had accused the defendants of belonging to the Islamic State group and plotting attacks against Christian churches and security forces, el-Masry said. The verdict, which came after an approval from Egypt's top religious authority, the Grand Mufi, can be appealed.

El-Masry said the defendants were tried for their involvement in a suicide bombing inside a Cairo chapel adjacent to St. Mark's Cathedral, the seat of Egypt's ancient Coptic Orthodox Church, in December 2016. The attack killed at least 25 people.

Some were convicted of plotting twin suicide bombings in churches in Alexandria and Tanta, on Palm Sunday in April 2017, killing at least 45 people, el-Masry said. Both attacks were claimed by the Islamic State group. Some were also convicted of killing eight police in a militant attack on a checkpoint in the Western Desert in January 2017.

The Palm Sunday bombings prompted President Abdel-Fattah el-Sissi to declare a state of emergency that is still in place.

Christians make up about 10 percent of Egypt's population. They have long complained of discrimination in the Muslim-majority nation and claim that authorities have often failed to protect them from sectarian attacks.

Rights group Amnesty International condemned the verdict, describing it as a "grossly unfair military trial" and demanding that the defendants receive a fair hearing before a civilian court.

"There is no doubt that the perpetrators of these horrific attacks should be held accountable for their crimes," said Najia Bounaim of Amnesty. "But handing out a mass death sentence after an unfair military trial is not justice and will not deter further sectarian attacks."

In Egypt, civilians accused of attacking members of the armed forces are tried before military courts, but civilians involved in militant attacks against civilians also face trials in military courts. Human rights groups criticize these trials for their hasty procedures, harsh sentences and limited transparency. The verdicts can be appealed, but any appeal would return to another military court.

Egypt has faced an Islamist insurgency since the 2013 removal of Muslim Brotherhood-affiliated President Mohammed Morsi. Retaliatory attacks have damaged or destroyed dozens of churches throughout the country. Security forces have struggled to contain militants led by an affiliate of the Islamic State group in the northern region of the Sinai Peninsula, but attacks on the mainland have also occurred.