As the divide grows between President Biden’s views on the Israel-Hamas war and those of his ex-aides, three former members of his administration are joining the calls for a ceasefire in Gaza. 

A letter signed on Thursday by the heads of a number of agencies and non-governmental organizations at the United Nations calls for an end to Israel’s counter-assault on Hamas and opposes the creation of safe zones to protect civilians in southern Gaza. Those pleas are a challenge to the president’s policy, which supports Israel’s right to defend itself given the continued threat posed by Hamas. 

Among the letter’s signatories who previously worked under Mr. Biden is the executive director of the United Nations International Children’s Emergency Fund, Catherine Russell, whom Mr. Biden lauded as “a trusted and indispensable advisor to Jill and me for nearly 30 years.” She previously served as assistant to the president and the director of the White House’s office of presidential personnel, and also worked on the Biden-Harris campaign. 

Another signatory formerly of Mr. Biden’s team is the director general of the International Organization for Migration, Amy Pope, who worked “first-hand” with Mr. Biden as his senior advisor on migration. The executive director of the World Food Program, Cindy McCain, the widow of Senator McCain, is also challenging the policy of the president who supported her elevation to that role. 

“I am not aware whether we had conversations with them in advance of this letter,” the spokesman for the Department of State, Matthew Miller, told reporters on Thursday. “I would say we of course supported all those nominees,” he said, “and support their ability and right and authority to make their independent judgments about what is the best policy.”

Asked whether it is “problematic” for former Biden employees to disagree with the administration’s policy, Mr. Miller said he was unsure whether the letter called for an immediate ceasefire. He pointed to the administration’s ongoing work with the Israeli government to protect civilians in southern Gaza from attacks launched by Israel, Hamas, and Palestinian Islamic jihadists.

“I think the letter points out that they are opposed to safe zones in which there is not agreement from all the parties not to attack those safe zones,” Mr. Miller added. “I think the point they’re making is if you direct people to go to safe areas, they have to be sure that those areas actually will be safe and not just targets for the civilians who have been moved there.”

Regardless of the specific actions proposed in the letter, it represents a widening rift between Mr. Biden’s stance on Israel and that of some of his current and former employees. On Tuesday, more than 400 members of his administration signed an open letter urging him “to urgently demand a ceasefire” and “to call for de-escalation of the current conflict by securing the immediate release of the Israeli hostages and arbitrarily detained Palestinians.” 

The letter, which also asks for the restoration of “basic services” and “adequate humanitarian aid” to Gaza, says it represents the views of “a coalition of Biden-Harris Administration political appointees and civil servants.” It first circulated about two weeks ago, NBC News reported, and has gained the signatures of senior and low-level administration employees working across federal agencies, departments, independent agencies, and the White House.

The most powerful body at the United Nations appears to be echoing these concerns. The Security Council backed a resolution on Wednesday calling for “urgent extended humanitarian pauses for [a] sufficient number of days to allow aid access” into Gaza. America and Britain abstained on that resolution, permitting it to pass.

The first UN resolution on the Israel-Palestine conflict since 2016, it was condemned by Israel’s ambassador to the UN, Gilad Erdan, for being “detached from the reality on the ground.”

“This council,” Mr. Erdan said, “still has not succeeded in condemning Hamas’s 7 October massacre. The resolution focuses solely on the humanitarian situation in Gaza [and] makes no mention of what led up to this moment.”

Mr. Biden, meanwhile, has defended his refusal to call for a ceasefire in Gaza. He told reporters on Wednesday that Hamas represents a continuing threat to Israel and that Israeli forces were seeking to avoid civilian casualties.

Mr. Biden added: “The IDF … acknowledge they have an obligation to use as much caution as they can in going after their targets. It’s not like they’re rushing to the hospital knocking on doors, you know, pulling people aside and shooting people indiscriminately.”