A top court on Saturday upheld a life sentence against Egypt's ousted Islamist president Mohamed Morsi on charges stemming from a trial over spying for Qatar, a judicial official and his lawyer said.

The court of cassation upheld a life sentence first passed in June 2016 on the charge of leading an illegal group but threw out a 15-year sentence on the charge of having stolen secret documents, his lawyer Abdel Moneim Abdel Maqsud told AFP.

A life sentence in Egypt amounts to 25 years in prison, and the court's rulings cannot be appealed.

Morsi, Egypt's first democratically elected president, was overthrown by the military in July 2013 following mass protests against his one-year rule.

The court also upheld death sentences for documentary producer Ahmed Ali Abdo, EgyptAir cabin crew member Mohamed Adel Kilani and university teaching assistant Ahmed Ismail Thabet, as well as a life term and 15 years for two others, the official said.

The trial hinged on accusations that the defendants had passed on state secrets to Qatar, an ally of Morsi's Islamist government that has denounced his overthrow.

Qatar has denied the charges.

Qatar is currently embroiled in a crisis with Egypt, Saudi Arabia and the United Arab Emirates which are boycotting the small Gulf emirate for its support for the Brotherhood, among other accusations.

Morsi, who came to power after the 2011 uprising that toppled longtime strongman Hosni Mubarak, was elected in 2012 and ruled for a year before his ouster.

His year in office was divisive and millions had taken to the streets demanding his resignation before the army toppled and detained him.

He has been sentenced separately to 20 years in prison over deadly clashes between protesters and security forces outside his palace in December 2012.

A court overturned a death sentence in another trial over prison breaks and violence during the 2011 revolt, pending a retrial.

Following Morsi's overthrow, a police crackdown killed hundreds of protesters who supported him.

Since his ouster, Egypt has been battling an insurgency by an Islamic State group affiliate based in North Sinai that has killed hundreds of policemen and soldiers and dozens of Coptic Christians.

Courts have sentenced hundreds of Islamists to death, including other Muslim Brotherhood leaders, though many have appealed and been granted new trials.

A veteran activist and engineering professor, Morsi emerged as a compromise candidate for the Brotherhood to field in Egypt's first democratic presidential election in 2012.

He narrowly won the vote but was soon accused of failing to represent all Egyptians and of trampling the ideals of the anti-Mubarak uprising.

Source: AFP