Human rights defenders rallied on Thursday to support the top UN expert on Palestinian rights, after the United States imposed sanctions on her over what it said was unfair criticism of Israel.

Italian lawyer Francesca Albanese serves as special rapporteur on human rights in the occupied Palestinian territories, one of dozens of experts appointed by the 47-member UN Human Rights Council to report on specific global issues.

She has long criticised Israeli treatment of the Palestinians, and this month published a report accusing over 60 companies, including some US firms, of supporting Israeli settlements in the West Bank and military actions in Gaza.

US Secretary of State Marco Rubio announced on Wednesday Albanese would be added to the US sanctions list for work which had prompted what he described as illegitimate prosecutions of Israelis at the International Criminal Court.

United Nations High Commissioner for Human Rights Volker Turk urged Washington to reverse course.

"Even in the face of fierce disagreement, UN Member States should engage substantively and constructively, rather than resort to punitive measures," he said.

Juerg Lauber, the Swiss permanent representative to the UN who now holds the rotating presidency of the Human Rights Council, said he regretted the sanctions, and called on states to "refrain from any acts of intimidation or reprisal" against the body's experts.

Mariana Katzarova, who serves as the special rapporteur for human rights in Russia, said her concern was that other countries would follow the US lead.

"This is totally unacceptable and opens the gates for any other government to do the same," she told Reuters. "It is an attack on UN system as a whole. Member states must stand up and denounce this."

Russia has rejected Katzarova's mandate and refused to let her enter the country, but it has so far stopped short of publicly adding her to a sanctions list.

Washington has already imposed sanctions against officials at the International Criminal Court, which has issued arrest warrants against Israeli Prime Minister Benjamin Netanyahu and his former defence minister for suspected war crimes in Gaza. Another court, the International Court of Justice, is hearing a case brought by South Africa that accuses Israel of genocide.

Israel denies that its forces have carried out war crimes or genocide against Palestinians in the war in Gaza, which was precipitated by an attack by Hamas-led fighters in October 2023.

"The United States is working to dismantle the norms and institutions on which survivors of grave abuses rely," said Liz Evenson, international justice director at Human Rights Watch.

The group's former head, Kenneth Roth, called the US sanctions an attempt "to deter prosecution of Israeli war crimes and genocide in Gaza".

The United States, once one of the most active members of the Human Rights Council, has disengaged from it under President Donald Trump, alleging an anti-Israel bias.