Egypt’s Court of Cassation rejected on Saturday a final appeal by Islamist militant Adel Habara against a death sentence for plotting an execution-style killing of 25 soldiers in an ambush in August 2013.

The court also rejected the appeals of 15 other defendants in the case whose sentences ranged from three years to life in prison.

Habara's lawyer Adel Moawad told Ahram Online that his client “is still on trial in other cases, including insulting the judiciary, attempted escape during transport, and [and has received another] death sentence for the murder of an informant in Sharkiya governorate.”

“However, today's death sentence is final and enforceable, and [the implementation of which] cannot be postponed until other cases are concluded.”

Habara, who gained notoriety over his reported involvement in the attack, is appealing another death sentence against him for his role in a major 2012 attack in North Sinai that left 16 soldiers dead.

Habara's death sentence has to reviewed by the country's Grand Mufti, though the Mufti's recommendation to the court is not legally binding.

The Egyptian government been battling an Islamist insurgency in North Sinai since the ouster of Islamist president Mohamed Morsi in 2013.

Militants have killed hundreds of army and police personnel. The army has said it has also killed hundreds of militants.