A Muslim Brotherhood's official spokesman has said that the killing of 25 Egyptian soldiers in Sinai earlier on Monday was meant to be a cover-up for the murder of 36 Islamist detainees on Sunday.

At least 25 recruits were killed and three were wounded on Monday when suspected militants fired rocket-propelled grenades at two buses carrying them in North Sinai.

Whereas 36 Islamists died at a Cairo prison on Sunday, in an incident that the authorities described as a thwarted jailbreak and the Brotherhood referred to as murder of innocents.

"We do not rule out that these killings are intended as a cover up for the serious qualitative and flagrant development in the case of assassinating Egyptians at the Abu Zaabal prison, where dozens were martyred,"Ahmed Aref, the Brotherhood's spokesman said in a statement on his official page.

Aref concluded his statement by calling on the Egyptians to preform prayers for the souls of those who died yesterday at the prison and today in Sinai.