More than 400 political appointees and staff members representing some 40 government agencies sent a letter to President Biden on Tuesday protesting his support of Israel in its war in Gaza.

The letter, part of growing internal dissent over the administration’s support of the war, calls on the president to seek an immediate cease-fire in the Gaza Strip and to push Israel to allow humanitarian aid into the territory. It is the latest of several protest letters from officials throughout the Biden administration, including three internal memos to Secretary of State Antony J. Blinken signed by dozens of State Department employees as well as an open letter signed by more than 1,000 employees of the U.S. Agency for International Development.

The signatories of the letter submitted on Tuesday and the one circulating among USAID employees are anonymous, the USAID letter explains, out of “concern for our personal safety and risk of potentially losing our jobs.” The signatories of the State Department dissent cables must disclose their names, but those cables have not been released publicly.

Although the Biden administration has recently started voicing concern over the high numbers of Palestinian civilians killed while urging Israel to show restraint, that budding criticism does not appear to be placating many in the U.S. government.

The letter, a copy of which was reviewed by The New York Times, began by denouncing the Oct. 7 attacks by Hamas, then urged Mr. Biden to stop the bloodshed caused by Israel’s retaliatory military campaign in Gaza.

“We call on President Biden to urgently demand a cease-fire; and to call for de-escalation of the current conflict by securing the immediate release of the Israeli hostages and arbitrarily detained Palestinians; the restoration of water, fuel, electricity and other basic services; and the passage of adequate humanitarian aid to the Gaza Strip,” the letter states.

Two political appointees who helped organize the letter to Mr. Biden said the majority of the signatories are political appointees of various faiths who work throughout government, from the National Security Council to the F.B.I. and the Justice Department.

Some of the signatories helped Mr. Biden get elected in 2020 and said in interviews they were concerned that the administration’s support of Israel’s war in Gaza clashed with Democratic voters’ stance on the issue.

“The overwhelming majority of Americans support a cease-fire,” the letter states, linking to a poll from October that shows that 66 percent of Americans, including 80 percent of Democrats, believe the United States should put pressure on Israel for a cease-fire.

“Furthermore, Americans do not want the U.S. military to be drawn into another costly and senseless war in the Middle East.”

Israel launched a ground invasion last month in Gaza in response to bloody attacks by Hamas on Oct. 7 that killed about 1,200 people, according to the Israeli government. So far, more than 11,000 Palestinians have been killed in Israel’s military offensive according to Gaza’s health ministry.