“Anyone who knows an advocate or a sheikh or a revolutionary should call him to urge him to mobilise,” a statement said.

There has already been an upsurge in militant violence since the generals ousted Mr Morsi, particularly in Sinai, long a hotbed of jihadist activity.

Intelligence reports have warned of a build-up of weapons, some stolen from Gaddafi arms stores in Libya, some headed for Gaza but held up by the block on smugglers’ tunnels.

On Sunday there were reports that gunmen killed a soldier in Sinai. On Friday night, a group of Islamists seized the North Sinai governor’s palace in the Mediterranean town of El Arish, raising the black Islamist flag. Earlier, jihadists attacked military checkpoints, a police station and El Arish airport. Five police and a soldier were killed.