The head of Egypt's al-Azhar mosque, the most revered institution in Sunni Islam, has warned of grave consequences if other countries follow America's lead and transfer their embassies to Jerusalem.Egypt's al-Masri al-Youm newspaper reported Thursday that the sheikh of al-Azhar, Ahmad al-Tayeb warned in a conversation with visiting former British prime minister Tony Blair that "if the door of moving foreign embassies to Jerusalem is opened, this will open the gates of hell." He added that such moves would "kindle the feelings of anger among all Muslims, endanger world peace and strengthen division and hatred around the world."The warning comes amid anger among Arab public opinion over US President Donald Trump's decision to recognize Jerusalem as Israel's capital and to start moving the US embassy there. At the request of the Palestinian Authority and Jordan, the Arab League will hold an emergency session Saturday to discuss Trump's move.Al-Tayeb said that mosques should devote the Friday sermon to "Jerusalem and action to support it and to refuse any effort to change its Arab identity." He said the speeches should "affirm the rights of the Arabs and Palestinians defined in international decisions."Egypt's Minister of Islamic Endowment, Mohammed Mokhtar Gomaa, also decided that the Friday sermon in all mosques in Egypt will be about Jerusalem, al-Masri al-Youm reported. The minister "called on all the Arabs to stand as one against any calls and attempts to change the identity of Arab Jerusalem or negate the rights of the Arabs," the paper said.