Benjamin Netanyahu has held his final pre-election cabinet meeting in the Palestinian territories, in a clear appeal to hardline nationalists two days before a vote in which he is fighting for his political life and possibly his freedom.

Locked in a knife-edge race and facing the prospect of criminal corruption charges, the Israeli prime minister promised last week to extend Israeli sovereignty over the Jordan Valley and settlements in the occupied West Bank. The move would likely leave its Palestinian inhabitants completely encircled and largely trapped in isolated enclaves.

Flanked by ministers in a marquee filled with Israeli flags in the settlement of Mevo’ot Yericho, Netanyahu said on Sunday that annexing the Jordan Valley – which straddles the Jordanian border and the northern Dead Sea – “guarantees that the [Israeli] military will be here forever”.

He said the expansion of Israel to the east would give the country “strategic depth”.

The cabinet also approved Mevo’ot Yericho as an official settlement, giving it a permanent status under Israeli law. It was the first time in nearly two decades that the government had held a meeting in the occupied territories, where more than 2.5 million Palestinians live under military rule among roughly 600,000 Israeli settlers.

Netanyahu speaks during the cabinet meeting held in the Jordan Valley. Photograph: Anadolu Agency/Anadolu Agency via Getty Images

Netanyahu has said he would declare the annexation after the election and hinted it might have already been approved by Washington, adding that his ally Donald Trump was likely to release his long-touted Middle East peace plan soon after the vote.

Naftali Bennett, one of Netanyahu’s former ministers, released on Sunday what he said was a map showing details of the unannounced peace plan, which has been a closely guarded secret.

The alleged plan, shared by Bennett on Facebook together with a map, showed the disputed city of Jerusalem and the Jordan Valley as part of Israel, while Jewish settlements in the West Bank were connected through a network of roads. Palestine was shown as a disjointed mass in the middle.

נתניהו, חשוף את המפה!



למה ראש הממשלה מקפיד לומר שהוא יחיל ריבונות על *היישובים* ולא על שטחי סי שמסביב?



למה שמענו את הגזר שבתכנית, ולא את המקל?



מדוע טראמפ הסכים לעכב את פרסום תכניתו למיד *לאחר* הבחירות?



מדוע ראש הממשלה מסתיר את מפת התכנית? pic.twitter.com/hrRuOJLhtR — Naftali Bennett בנט (@naftalibennett) September 15, 2019

However, Bennett, a far-right ultranationalist who is running against Netanyahu, released the plan in an effort to show that the prime minister was not doing enough to expand Israeli control over Palestinian land.

Bennett, who wants Israel to annex the majority of the West Bank, called the map “hell” for settlers as they would be “islands in an ocean of Palestine”.

The Guardian contacted the US government for comment. Israeli media cited unnamed US officials denying the map was accurate.

Israel is due to hold its second election in five months after Netanyahu, the country’s longest-serving prime minister, was unable to form a coalition government. Facing political defeat, he forced a repeat election.

Final opinion polls released on Friday suggest razor-thin margins between his ruling Likud party and the centrist Blue and White alliance led by the former military chief Benny Gantz. It is possible there will be no clear winner, which could kick off weeks of political deal-making with smaller parties to decide Israel’s next government.

Netanyahu has sought to play up his diplomatic acumen and relationships with strongman leaders, especially Trump, to convince voters they need him. Trump said on Saturday that he and Netanyahu had spoken about a possible US-Israeli defence treaty, comments seen as an 11th-hour election gift to the prime minister.

As in previous elections, the 69-year-old leader has been accused of overtly racist messaging that demonises the country’s substantial Arab minority.

His Likud party has issued unfounded warnings that the election could be stolen through voter fraud in Arab areas, a move slammed as a scaremongering attempt to rally voters who fear their political power. And on Thursday, Facebook temporarily shut down a chatbot on the prime minister’s official page for breaching the company’s hate speech policy after it warned of Arabs who “want to destroy us all”.

Israel’s Arab parties are expected to win significant seats after reunifying into a single alliance, similar to 2015 when they became the third-largest force in the Knesset. It is possible they could gather enough seats to block Netanyahu from continuing as prime minister.

Polls also show the far-right extremist Jewish Power party, whose members have called for the expulsion of Arabs, could enter parliament. If it does, Netanyahu is expected to bring it into a coalition government.