Updated

Egyptian jetfighters are staging celebratory flights over Cairo, ushering in a commemoration of the 40th anniversary of the nation's last war with Israel on a day when rival rallies by supporters and opponents of the ousted Islamist president carry the potential for violence.

Security forces are deployed across much of the Egyptian capital in anticipation of clashes.

Sunday's rallies in Tahrir Square, birthplace of the 2011 uprising against autocrat Hosni Mubarak, are likely flashpoints. Authorities have vowed not to allow supporters of the ousted Mohammed Morsi into the square.

The possibility of bloodshed on an occasion revered by most Egyptians is seen as a sign of the schism that began soon after Morsi's narrow election victory in 2012.

He was ousted in a July 3 coup.