Egypt's deposed Islamist president Mohamed Morsi will be tried on charges of giving Qatar documents relating to national security, the state prosecutor said Saturday.
The former head of state already faces the death penalty in several trials, and his supporters have been the target of a deadly crackdown by the authorities since his ouster in July 2013.
No date has yet been set for the new trial for Morsi, who is suspected of providing the sensitive documents to the energy-rich Gulf state during his single year of turbulent rule.
Morsi and 10 co-defendants will go on trial for having "handed over to Qatari intelligence documents linked to national security... in exchange for one million dollars (772,000 euros)," a statement said.
This case represents "the biggest act of treason carried out by the Muslim Brotherhood against the country," the prosecutor's statement added.
Morsi's Brotherhood was designated a terrorist organisation after his overthrow.
Co-defendants include Morsi's former secretary, Amin El-Serafi; the ex-director of his office, Ahmed Abdel Atti, and Ibrahim Mohamed Helal, identified as a chief editor of the Doha-based Al-Jazeera television network.
In the statement, the prosecutor said Morsi and Abdel Atti gave El-Serafi "extremely sensitive documents concerning the army, its deployment and weaponry" and he in turn gave them to Helal and to a Qatari intelligence operative.
It said intermediaries, who were not identified, were used to send the documents to Helal and the Qataris.
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The papers included documents from the "general and military intelligence offices of the state security" apparatus, the prosecutor said.
Morsi, El-Serafi and Abdel Atti are all behind bars. Helal's whereabouts are unknown.
In March, the interior ministry accused El-Serafi of handing over to an Al-Jazeera chief editor and Brotherhood member documents regarding the army, its weaponry and troop deployments.
Relations between Egypt and Qatar soured after Morsi's ouster, as Cairo criticised Doha's backing for the Brotherhood.
Qatar has denounced Egypt's crackdown on Morsi supporters which has left more than 1,400 people dead.
Thousands more have been detained and imprisoned, and hundreds have been sentenced to death in speedy mass trials.
Morsi is already on trial in three separate cases -- one for the killing of protesters during his presidency, another for allegedly conspiring with foreign powers including Iran to destabilise Egypt, and a third over a jailbreak during the 2011 uprising that ousted president Hosni Mubarak.
Morsi could face the death penalty if convicted.
Egypt has also jailed Al-Jazeera journalists on charges of helping the Brotherhood, triggering an international outcry.