The Organisation of Islamic Cooperation (OIC) on Sunday expressed its "total rejection" of the Israeli prime minister's pre-election pledge to annex part of the West Bank, Saudi state media said.
Battling to win re-election in polls on Tuesday, Benjamin Netanyahu made a deeply controversial promise last week to annex the strategic Jordan Valley, which accounts for around a third of the occupied West Bank.
He also repeated his intention to annex Israeli settlements in the wider West Bank, but in coordination with US President Donald Trump.
After an emergency foreign ministers' meeting in the Red Sea city of Jeddah, the OIC expressed "its total rejection and strong condemnation of the Israeli Prime Minister's declaration".
"This dangerous declaration... deliberately undermines international efforts to achieve a just and lasting peace... and pushes the whole region towards further violence and instability," the 57-member pan-Islamic body added in a statement carried by Saudi state media.
The emergency meeting of OIC foreign ministers was called at the request of Saudi Arabia, which has unilaterally condemned Netanyahu's pledge as a "dangerous escalation".
The multilateral statement comes as Netanyahu's government on Sunday approved a new settlement in the occupied West Bank.
The Israeli cabinet agreed to turn the wildcat settlement of Mevoot Yericho in the Jordan Valley into an official settlement, the premier's office said.
Netanyahu's moves could essentially destroy any remaining hopes for a two-state solution to the Israeli-Palestinian conflict.
His pledge to annex the Jordan valley has drawn firm condemnation from the Palestinians, the United Nations, the European Union and Arab states.