Under a coalition agreement with Benjamin Netanyahu’s Likud party, a far-right politician named Itamar Ben-Gvir will serve as Israel’s minister of national security in what is expected to be the most right-wing administration in the nation’s history.

The agreement was reached after Netanyahu’s right-wing coalition easily won Israel’s fifth parliamentary election in less than four years this month.

Netanyahu is still continuing talks with three other parties on forming the new government.

“We took a big step (last night) towards a full coalition agreement, toward forming a fully, fully right-wing government,” Ben-Gvir, leader of the Jewish Power party, said in a statement.

Ben-Gvir, who was convicted in 2007 of racist incitement against Arabs and backing a group considered by Israel and the United States to be a terrorist organization, will have an expanded security portfolio that will include responsibility for Border Police in the occupied West Bank.

The Palestinian Authority’s Foreign Affairs Ministry said the appointment would have a “potentially catastrophic impact on the Israeli-Palestinian conflict” and hinder the revival of negotiations between the two sides.

Mairav Zonszein, senior Israel analyst at International Crisis Group, said Ben-Gvir’s expanded security portfolio could be a “game changer” in the West Bank, which is under the effective control of the Israeli military.

Granting Ben-Gvir authority over Border Police in the West Bank “is a form of blurring the boundaries between Israel and the West Bank”, she added.

Israel captured the West Bank, Gaza and East Jerusalem – areas that Palestinians want for a state – in a 1967 war. U.S.-sponsored negotiations stalled in 2014 but the expansion of Israeli settlements has continued despite international opposition.

Hazem Qassem, a spokesperson for the Islamist Hamas group that governs Gaza, said Ben-Gvir’s deal with Netanyahu meant the new government in Israel would be “more fascist and extreme”.

The militant Islamic Jihad group also predicted further tension.