Arab foreign ministers late on Saturday urged the United States to abandon its decision to recognise Jerusalem as Israel's capital, saying the move would increase violence throughout the region.
The announcement by President Donald Trump on Wednesday was a "dangerous violation of international law", had no legal impact and was "void", the Arab League said in a statement after a session attended by all its members in Cairo.
Trump's endorsement of Israel's claim to all of Jerusalem as its capital would reverse long-standing US policy that the city's status must be decided in negotiations with the Palestinians, who want East Jerusalem as the capital of their future state.
"The decision has no legal effect … it deepens tension, ignites anger and threatens to plunge region into more violence and chaos," the Arab League said at 3 a.m. local time after hours of meetings that began on Saturday evening.
It said it would seek a UN Security Council resolution rejecting the US move.
Lebanon's Foreign Minister Gebran Bassil said during the emergency meeting that Arab nations should consider imposing economic sanctions against the United States to prevent it moving its Israel embassy to Jerusalem from Tel Aviv.
"Pre-emptive measures (must be) taken … beginning with diplomatic measures, then political, then economic and financial sanctions," he said, without giving specific details.
The Arab League statement made no mention of economic sanctions.
Arab criticism of Trump's plan contrasted sharply with the praise Washington's traditional Arab allies heaped on him at the beginning of his administration in January.
Most countries consider East Jerusalem, which Israel annexed after capturing it in a 1967 war, to be occupied territory, and say the status of the city should be left to be decided at future Israeli-Palestinian talks.
While the international community has almost unanimously disagreed with Donald Trump's announcement, reports suggest that the announcement was done with the pre-agreement of Egypt and Saudi Arabia, with the Saudi Arabia going as far as, allegedly, stating to the Palestinian President to accept a village on the outskirts of Jerusalem as the alternative Palestinian capital.
Since the announcement, Saudi Arabia's royal court has sent notices to the nation's media outlets to limit the airtime given to protests against Trump's announcement.
Emboldened by Trump's annoucement, Israeli housing Minister Yoav Galant decided on Friday to promote a plan to build 14,000 new settlement units in the occupied Jerusalem.