Nickolay Mladenov
Nickolay MladenovFlash 90

The UN's Middle East envoy warned on Thursday that Israel's plan to apply sovereignty over parts of Judea and Samaria may fuel extremism and ignite a regional conflict.

Such a move could do irrevocable damage to Israeli-Palestinian relations, and also turn Palestinians towards extremism, said UN envoy Nickolay Mladenov, according to AFP.

If Palestinians "feel that there is no prospect of a peaceful resolution to the conflict, that only creates opportunities for radicals," he told journalists in Jerusalem.

Mladenov pointed to a "long litany of such developments" in the Middle East, referring to the rise of the Islamic State group in Iraq and Syria.

"You leave a vacuum, you take away a political prospect, you take away a positive agenda, and very quickly somebody comes and fills it with a negative and very destructive agenda," he warned.

Mladenov was speaking a day after a UN Security Council session in which Secretary General Antonio Guterres, as well as European and Arab powers, called on Prime Minister Binyamin Netanyahu to end his sovereignty ambitions.

A day earlier, Guterres urged Israel to drop the sovereignty plans, saying they would be a "most serious violation of international law."

While countries are yet to announce retaliatory measures, Mladenov warned on Thursday that the Israeli move could spark a regional conflict.

"Nobody wants another war, another flare-up of violence in the Middle East, and certainly not one that has such a potential to ignite conflict way beyond its borders," he said.

Mladenov’s comments came days after he attended a rally against sovereignty initiated by the Palestinian Authority.

"The United Nations believes that the Israeli annexation process violates international law," Mladenov said at the rally.

"This is not only contrary to the law, but it is also hurting and effectively destroying the Palestinians' hope of establishing a state. We must work to bring Israelis and Palestinians back to the negotiating table for a peace agreement and the establishment of a Palestinian state alongside Israel," he added.