UNITED NATIONS, Sept. 11 (Xinhua) -- UN Secretary-General Antonio Guterres on Wednesday voiced concern over Israeli Prime Minister Benjamin Netanyahu's stated intention to annex the Jordan Valley and adjacent northern Dead Sea in the occupied West Bank.

Netanyahu said Tuesday that he would annex these territories, if he wins the Sept. 17 election, as a first step to applying Israeli sovereignty over all settlements and other areas in the occupied West Bank.

In a statement, Guterres' spokesman Stephane Dujarric said such steps, if implemented, would constitute a serious violation of international law.

"They would be devastating to the potential of reviving negotiations and regional peace, while severely undermining the viability of the two-State solution," Dujarric said.

He added that the United Nations remains committed to supporting Palestinians and Israelis to resolve the conflict on the basis of relevant United Nations resolutions, the Madrid terms of reference, as well as in compliance with prior agreements between the Israeli government and the Palestine Liberation Organization, and realizing the vision of two states living side by side in peace and security within recognized borders, on the basis of the pre-1967 borders.