The United Nations has called on Israel to reverse a decision to cancel the work permit of Omar Shakir - the Israel and Palestine Director for Human Rights Watch.
Mr Shakir, who is based in Jerusalem, had his permit rescinded on May 7th.
UN human rights experts say the decision "appears connected solely to his human rights research and advocacy", and "not to any allegation of wrongdoing".
The UN experts are Michael Lynk, David Kaye and Michel Forst.
"Deporting Mr Shakir sends a troubling message that Israel resists the kind of human rights fact-finding and debate that Human Rights Watch and other domestic and international non-governmental organisations conduct all of the time, in almost every part of the world.", the group says.
In March 2017, Israel initially refused to grant a work permit for Mr Shakir.
At the time, UN experts urged the Israeli government to fully respect the fundamental rights and freedoms of human rights defenders and organisations, and to withdraw and rescind all restrictive legislation targeting human rights defenders.
They are renewing their call in this fresh appeal.
According to public reports and statements, the Israeli government cancelled Mr Shakir's work permit in light of his alleged advocacy in the past for the boycott, divestment and sanctions (BDS) movement.
Human Rights Watch has stated that it does not take a position on the BDS movement, nor do its employees.
"A troubling trend"
In a statement, the UN experts add: "We fear that this decision is part of a troubling trend by the Israeli government to restrict and shrink the space of human rights defenders who are critical of its record in the Occupied Palestinian Territories.
"We have previously identified concerns, for example, with Israel’s restrictions on human rights NGOs."
The UN experts, while taking no position on BDS, remind the government that expressing support for or opposition to BDS remains firmly protected by the rights to freedom of opinion and expression.
"We are concerned that Israel is denying a voice in the country to well-respected organisations and human rights advocates,” the experts said, noting as well the 14-hour detention and questioning and eventual expulsion of two human rights lawyers from the United States who were attempting to visit Israel on 29th of April".
UN experts call on #Israel to rescind its decision of 7 May to cancel the work permit of @OmarSShakir, the Israel & Palestine Director for @HRW, who is based in Jerusalem: https://t.co/lElpfi0NCF pic.twitter.com/IPMANbsvlN
— UN Human Rights (@UNHumanRights) May 18, 2018
"The ability of human rights organisations to function freely in any country is a barometer of the larger enjoyment of rights for the residents of that country.
"The unjustified curtailing of the indispensable work of human rights defenders does not dignify the reputation of any government, and runs counter to democratic values," they emphasise.
It comes amid escalating tensions in the region, following the killing of 58 people by Israeli forces at the Gaza border earlier this week.
While the European Union Heads of Missions in Jerusalem and Ramallah say they are "deeply concerned" about plans by Israeli authorities to demolish the community of Khan al Ahmar.
