Israeli PM Benjamin Netanyahu has vowed to annex part of the occupied West Bank on the border with Jordan if he is voted back into office next week.
Mr Netanyahu said he would apply "Israeli sovereignty over the Jordan Valley and northern Dead Sea".
Such a move would be popular with right-wing parties which he would have to depend upon to form a coalition but fiercely opposed by Palestinians.
Israel has occupied the West Bank since 1967 but stopped short of annexation.
Palestinians claim the whole of the West Bank for a future independent state. Mr Netanyahu has previously insisted that Israel would always retain a presence in the Jordan Valley for security purposes.
Israel occupied the West Bank, along with East Jerusalem, Gaza and the Syrian Golan Heights, in the 1967 Middle East war. It effectively annexed East Jerusalem in 1980, and the Golan Heights in 1981, although neither move was accepted internationally for decades.
The Trump administration has since recognised both steps, overturning previous US policy.