The UN special coordinator for the Middle East Peace Process warned Wednesday against Israel’s plan to annex all or part of area C in the West Bank.

“If [the plan is] implemented, it would deal a devastating blow to the potential of reviving Israeli Palestinian negotiations, advancing regional peace, and the essence of the two-state solution,” Nickolay Mladenov said in a statement.

Israeli Prime Minister Benjamin Netanyahu and his rival in the Blue-White Party, Benny Gantz, promised to annex the Jordan Valley, northern Dead Sea and settlements in the occupied West Bank if they win the upcoming Israeli elections in early March.

Roughly 650,000 Israeli Jews currently live on more than 100 settlements illegally built since 1967, when Israel occupied the West Bank and East Jerusalem.

Palestinians insist in regaining the entire West Bank along with the Gaza Strip for the establishment of a future Palestinian state.

International law views the West Bank and East Jerusalem as occupied territories and considers all Jewish settlement-building activity there illegal.