The supreme guide of the Muslim Brotherhood, the movement which Egypt's President Mohamed Morsi belongs to, called on Thursday for a jihad (holy war) to liberate Jerusalem from Israeli rule.
"Jerusalem is Islamic ... and nobody is entitled to make concessions" on the Holy City, said Sheikh Mohammed Badie in his weekly message to supporters, according AFP.
"The jihad for the recovery of Jerusalem is a duty for all Muslims," he said, stressing that the liberation of the Holy City "will not be done through negotiations or at the United Nations."
Israel, which signed a peace treaty with Egypt in 1979, has watched with concern as Islamists were catapulted to the forefront of politics following a popular uprising that toppled president Hosni Mubarak last year.
Morsi has repeatedly said he would respect international treaties signed by Cairo. But there have also been multiple calls from Cairo to "revise" the accords.
The United States under Barack Obama appeared to throw Mubarak under a bus and to almost welcome the Muslim Brotherhood's takeover, a fact that has served to heighten Israel's anxiety over the future stability of the region.