An Egyptian court has referred the case of 13 defendants facing terrorism charges to the country's top religious authority, the Grand Mufi, for a non-binding opinion on whether they can be potentially executed as the prosecution seeks.

The Ismailia Criminal Court says Monday that they are members of a local affiliate of the Islamic State group in the restive northern Sinai peninsula.

The men are accused of killing two people, including a police officer, while trying to escape from their prison in the Suez Canal city of Ismailia in October.

The verdict can be appealed, and the presiding judge may rule independently of the Mufti. The verdict is set for July 12.

Egypt has struggled to contain a long-running Islamic insurgency in Sinai.