The United Arab Emirates has warned Israel that annexing the occupied West Bank would cross a "red line" and undermine the spirit of the Abraham Accords that normalised relations between the two countries.
A senior Emirati official, Lana Nusseibeh, said such a move would be the death knell of the two-state solution to the Israeli-Palestinian conflict.
The Palestinian Authority's foreign ministry said it welcomed the UAE's position.
The Israeli government has not commented. But Nusseibeh's remarks came after far-right Finance Minister Bezalel Smotrich unveiled a proposal for the annexation of approximately four-fifths of the West Bank.
Israel has built about 160 settlements housing 700,000 Jews since it occupied the West Bank and East Jerusalem - land Palestinians want, along with Gaza, for a hoped-for future state - during the 1967 Middle East war. An estimated 3.3 million Palestinians live alongside them.
The settlements are illegal under international law.