CAIRO (AFP) - Deposed Islamist president Mohamed Mursi was on Sunday facing charges of espionage and carrying out "terror attacks" in Egypt, as a third trial against him was due to get under way.

The latest court case is part of a relentless government crackdown targeting Mursi and his Islamist supporters since he was ousted by the military on July 3.

Mursi and 35 others, including former aides and leaders of his Muslim Brotherhood, are accused "of spying for the international organisation of the Muslim Brotherhood, its military wing and the (Palestinian) Hamas movement".

They are also charged with "carrying out terror attacks inside the country against state property, institutions and their employees to spread chaos".

If found guilty, the defendants could face the death penalty.

Mursi, who was ousted by the military after a single year of turbulent rule, is already on trial for his alleged involvement in the killing of opposition protesters in December 2012.

Along with 130 others, including dozens of members of Hamas and Lebanon's Shiite militant movement Hezbollah, Mursi is separately being tried on charges linked to a jailbreak during the 2011 uprising that toppled strongman Hosni Mubarak.

The ousted leader is also to be tried separately for "insulting the judiciary". A date for that has yet to be set.

During Mursi's short-lived presidency, ties between Cairo and Hamas, a Palestinian affiliate of the Muslim Brotherhood which rules the neighbouring Gaza strip, had flourished.

But since July, Egypt's military-installed government has accused Hamas of backing Morsi and his Brotherhood and carrying out terrorist attacks inside Egypt.

The army has destroyed several hundred tunnels used to ferry crucial supplies, including fuel, into the blockaded Gaza Strip.

Since Mursi's ouster, his supporters have faced a relentless crackdown by Egypt's government that has left more than 1,400 people dead according to Amnesty International, and seen thousands more arrested.