The United Nations Special Rapporteur on the Occupied Palestinian Territories said on Thursday that Israel's decision to withdraw from the U.N. Human Rights Council was "extremely serious".

Earlier, Israeli Foreign Minister Gideon Saar said his country had informed the UNHRC that it was following the United States in withdrawing from the Council, accusing it of "ongoing and unrelenting institutional bias" against Israel.

"It shows the hubris and the lack of realisation of what they [Israel] have done. They insist in self-righteousness, that they have nothing to be held accountable for, and they are proving it to the entire international community," Francesca Albanese told Reuters.

Albanese said she feared Israel's "genocide" against the Palestinians would expand and intensify on the West Bank, which Palestinians want along with Gaza as the core of a future independent state.

Israel denies accusations that it is committing genocide and says it is protecting its legitimate security interests in both the West Bank and in Gaza, where a fragile ceasefire now holds after a 16-month war against the Islamist militant group Hamas.

"The north (of the West Bank) is being attacked primarily by soldiers. The south has been attacked primarily by (Israeli) settlers, and you can see this as an assault on the Palestinian people as a whole," Albanese said.

Commenting on U.S. President Donald Trump's surprise proposal this week that the United States could "take over" Gaza, Albanese said: "Trump is destroying the basic principles of respect for human rights across a huge spectrum, not just in Palestine... We have moved further towards the abyss."

"I'm surprised that European states are staying silent instead of rising up and saying,: 'This is utter nonsense, and we will not tolerate this'," she added.