A group of more than 800 government officials in the U.S., Britain and major European countries ― as well as European Union institutions ― has signed a letter urging Western countries to reconsider their policy of near-total support for Israel’s devastating offensive in Gaza.

The letter, released Friday, urges those governments to use all possible leverage, including potentially cutting off military support for Israel, to secure a cease-fire in Gaza that will increase aid for Palestinians and bring the release of Israeli hostages captured by Hamas and other militants on Oct. 7. It’s the latest sign of deep alarm among foreign policy professionals about the path President Joe Biden and other world leaders have chosen since the attack and Israel’s retaliation began.

“We are expected as civil servants to respect, serve and uphold the law while implementing policies, regardless of the political parties in power… we have done so for our entire careers,” says the letter, also signed by people working for the French, German and Swiss governments, among others. “We have internally expressed our concerns that the policies of our governments/institutions do not serve our interests and called for alternatives that would better serve national and international security, democracy and freedom; reflect the core principles of western foreign policy; and incorporate lessons learned. Our professional concerns were overruled by political and ideological considerations.”

Frustration among national security experts inside the governments that Israel counts as its key international supporters is at an all-time high.

Earlier this week, Secretary of State Antony Blinken held a town hall-style meeting with State Department employees, a significant group of whom have signed so-called dissent cables challenging Biden’s Gaza policy. At the meeting, one staffer told Blinken that State Department employees are receiving messages daily from people in Gaza who have previously been involved in U.S. government programs and are asking what more the U.S. could do to end the conflict ― winning huge applause from attendees of the session, a State Department official told HuffPost.

State Department spokespeople did not respond to a HuffPost request for comment on the incident.

Josh Paul, a veteran State Department official whose resignation over the U.S. Gaza policy was first reported by HuffPost, helped organize the Friday letter, whose signatories are anonymous for fear of professional retaliation. In a statement regarding the message, Paul argued: “One-sided support for Israel’s atrocities in Gaza, and a blindness to Palestinian humanity, is both a moral failure, and, for the harm it does to Western interests around the globe, a policy failure.”

“This is a remarkable statement from hundreds of individuals who have devoted their lives to building a better world, and, at a time where our politicians seem to have forgotten them, it is a much-needed reminder of the core values that bind the transatlantic relationship, and a proof that they endure,” he continued.

The letter is expected to continue to attract signatures in the coming days.

The Netherlands, one of the wealthiest countries in Europe and the host of significant global institutions, such as the International Court of Justice (ICJ), has seen a significant uproar, with civil servants last month demonstrating outside the Foreign Ministry building.

“The Netherlands pretends to be the international rule-of-law and human-rights capital of the world, and look at us,” said Berber van der Woude, a former Dutch diplomat who was stationed in the occupied West Bank.

She argued that the message “shows that people who are experts, who have diplomatic experience… who have been serving the country for ages and have been doing that very loyally are so worried.”

“They would never choose to do this if it were not something very serious. It is a very exceptional situation, especially after the ICJ order,” said van der Woude, referring to the court’s ruling last week that there is a plausible risk of genocide in Gaza and that the Israeli offensive there must change course.

Angélique Eijpe, a 21-year veteran of the Dutch foreign ministry, resigned over her government’s approach in November. She said that signing the Friday letter was “an extraordinary thing for all involved to do.”

She told HuffPost that following the Oct. 7 attack, she tried to warn the foreign minister against Israel’s response, noting comments from Israeli ministers that demonstrated “genocidal intent.”

“I warned that I saw a parallel with our decision-making in the context of the Iraq War, where we also put all critical assessments of the situation aside because there was already a political decision made,” Eijpe said.

The government responded with “minimal expressions of concern for our well-being,” she said ― an echo of the listening sessions and town halls the Biden administration has offered to U.S. officials deeply disturbed by the moral and strategic implications of Washington’s choices.

“This type of concern is nice, but it also cast doubt on the professionalism of our concerns,” Eijpe said. American officials internally challenging the policy have cited national security arguments in doing so, and in November, HuffPost revealed that dozens of U.S. counterterrorism experts had privately written to the head of their agency saying Biden’s approach risked fueling blowback and undermining cooperation with other countries.

In her resignation note, Eijpe noted she is the breadwinner for her children and her decision to resign was difficult. But she compared it to the toll of the choices of her ancestors amid the Holocaust in the 1940s and Palestinians dying daily in Gaza today.

“Ultimately, I have the immense privilege of paying a relatively insignificant price to be on the right side of history,” Eijpe wrote.