France, Germany, Spain, Italy and the United Kingdom collectively condemned Netanyahu's Tuesday announcement that Israel would annex a third of the West Bank if he was re-elected. (For the latest election polls - click here)

The five European powers issued a statement on Thursday saying the move to bring the Jordan Valley and the area north of the Dead Sea under Israeli sovereignty would be a "serious breach of international law."

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They were "deeply concerned," the statement said, adding that they would "continue to call on all parties to refrain from actions in contravention of international law which would imperil the viability of a two-state solution, based on the 1967 lines." They concluded by renewing their "commitment to Israel's security," condemning "recent attacks on Israel from Gaza"

Prime Minister Netanyahu, who is in the last throes of a crucial re-election campaign, announced at a press conference on Tuesday that he would begin annexation proceedings in the Jordan Valley and the Northern Dead Sea if he won the election, in coordination with the Trump administration.

"In recent months I have led a diplomatic effort in this direction, and the conditions for this have ripened," Netanyahu said in the address, which was publicly broadcast, and earned his Likud party a fine for electioneering. The prime minister is convinced that the Trump administration's Middle-East peace plan is set to lay favorable groundwork for the policy.

This is not the first time Netanyahu floats the idea of annexing the Palestinian territory, and not the first time he does it to curry electoral favor. Days before the April elections, he told Israel's Channel 12 that he would extend Israeli sovereignty over the West Bank if elected. "A Palestinian state will endanger our existence," he told the program 'Meet the Press' at the time.

Open gallery view Israeli Prime Minister Benjamin Netanyahu points out the Jordan Valley, an area he has declared Israel will annex, as he gives a statement in Ramat Gan. September 10, 2019. Credit: AFP

Campaigning Netanyahu told the interviewer that he made "no distinction between settlement blocs and isolated ones," but applying any kind of selective sovereignty in the West Bank is problematic. It runs the risk of created segregated areas, in which small groups of Israeli citizens will be completely brought under Israeli jurisdiction, while their Palestinian neighbors remain subject to the IDF and its judicial apparatus.

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The Jordan Valley, although sparsely populated, is a large area, divided into two administrative regions, the Jordan Valley regional council to the north, and the Megilot regional council in the south. If the map published by the prime minister's office at his Tuesday announcement is accurate, the immediate annexation would also bring in two other settlements on the Jordan Valley borders: Ma'ale Efraim and Kochav Hashachar. More than 3,000 live in the two towns.

According to Israeli human rights NGO B'Tselem, the combined area of the Jordan Valley and the northern Dead Sea is around 1,600 square kilometers (1.6 million dunams), which represents about 30% of the West Bank. Around 65,000 Palestinians and 11,000 settlers lived in this area, which includes the city of Jericho, in 2016. The settlements are mainly agricultural, and many of the settlers in the area are not religious.