Israeli Prime Minister Benjamin Netanyahu has pledged to annex the Jordan Valley in the occupied West Bank if he is re-elected on September 17.
Mr Netanyahu said the move would be a first step, with other settlements to follow after the publication of US President Donald Trump's peace plan for the region.
"Today I announce my intention, after the establishment of a new government, to apply Israeli sovereignty to the Jordan Valley and the northern Dead Sea," he said in a live broadcast on Israeli TV.
Mr Trump's peace plan is due to be unveiled after next week's election.
The plan would present “a historic, one-time chance to extend Israeli sovereignty over our settlements in Judea and Samaria, and also to other areas important to our security, our heritage and our future,” he said, using the Biblical Hebrew names for the West Bank.
“I ask you to give me a clear mandate to extend Israeli sovereignty over all the settlements."
Mr Netanyahu said his annexation plans would not include Palestinian cities such as the Jordan Valley's Jericho.
The area has been occupied by Israel since the 1967 war. It makes up a quarter of the West Bank and is crucial to the prospect of a future Palestinian state.
More than 400,000 Israelis live in West Bank settlements that are considered to be illegal under international law. About 2.7 million Palestinians live in the territory.
“If Prime Minister Netanyahu is allowed to implement his plans of annexation, he would have succeeded in burying any chance of peace between Palestinians and Israelis,” said Saeb Erekat, secretary general of the Palestine Liberation Organisation.
“The international community must stop such madness. We need to end the conflict and not to keep it for another 100 years.”
Hanan Ashrawi, another senior Palestinian official, told AFP on Tuesday: "He is not only destroying the two-state solution, he is destroying all chances of peace.
"This is a total game changer."
Ministers from the Arab League took similar issue with Mr Netanyahu's election pledge.
League Secretary General Ahmed Aboul Gheit said after a meeting of Arab foreign ministers in Cairo that the move would undermine any chances of progress in the Palestinian-Israeli peace process.
Saudi Arabia has condemned Mr Netanyahu's move and called an emergency meeting of the Organisation of Islamic Co-operation's group of foreign ministers, state TV reported.
In May, Commanders for Israel’s Security, a nonpartisan group of about 300 retired senior military and security officers, warned Mr Netanyahu that extending sovereignty to parts of the West Bank would lead to the collapse of the Palestinian Authority and a violent power vacuum.
But the Israeli leader became even more determined.
“Swaths of land in Judea and Samaria are not just a guarantee of Israel’s security, they are also our patrimony,” he tweeted in response.