The Arab League and the top Sunni Muslim religious authority have criticized the relocation of the U.S. Embassy from Tel Aviv to contested Jerusalem.
The Cairo-based Arab League called on the international community to oppose what it considers an "unjust decision" and the ongoing "Israeli occupation" of the city.
It called the move a "blatant attack on the feelings of Arabs and Muslims," and a "grave violation of the rules of international law" that would destabilize the region.
The Palestinians, who claim east Jerusalem as the capital of their future state, have called for an urgent meeting at the Arab League on Wednesday to discuss the matter.
Egypt's Al-Azhar religious institution called on the international community to use "all peaceful means" to "dismiss positions of countries that sided with the Zionist entity," referring to Israel.
The US is to formally inaugurate the embassy in Jerusalem later on Monday.
The Palestinians are holding mass protests along the Gaza border to condemn the move, and to try to break a decade-old blockade of the Hamas-ruled territory by Israel and Egypt.