Tel Aviv is expelling a top Human Rights Watch official because of allegations he supports the boycott of Israel, a movement activists use to protest the treatment of the Palestinians.

Israel's Supreme Court upheld the government's order that Omar Shakir, the HRW's director of Israel and Palestine, has to leave the country Monday.

Israel has denied entry to others who it says support the boycott, including United Nations diplomats. But this is the first time someone inside the country has been ordered to leave.

"The court has now put the veneer of legality on the Netanyahu government's assault on human rights advocacy and that's a dangerous precedent that will affect many other people," Shakir said. "Not just human rights advocates, but ordinary students that study at Israeli universities, spouses of Israelis who engage in mainstream criticism and advocacy."

He said Israel can apply the same logic of criticizing the boycott to those who call the West Bank an occupied territory and believe Jewish settlements are illegal, including the International Criminal Court, Shakir said.

Human Rights Watch Executive Director Kenneth Roth said he thinks this is the first time a democracy has thrown a researcher out of the country.

"I think it demonstrates the increasingly constrained nature of Israeli democracy," Roth said, noting that the only other countries that have expelled HRW staffers include Iran, North Korea and Venezuela.

Shakir said Human Rights Watch does not have an official position on the boycott and he has never spoken out in favor of it as an HRW representative. But he said HRW believes in the right to free speech, including the right to speak in favor of a boycott.

Israeli authorities have cited what they say are pro-boycott comments made by Shakir before he joined HRW.

Advocates of the Boycott, Divestment and Sanctions (BDS) movement are pushing for an overall economic boycott of Israel, saying a boycott of South Africa in the 1980s pressured that government to scrap its racist apartheid system.

Boycott supporters deny Israel's allegation that they are anti-Semitic.

Israel passed a law in 2017 subjecting anyone who speaks out for the boycott to deportation.