Hundreds of State Department officials ignored a warning from the White House, voicing their opposition to President Trump Donald John TrumpObama calls on Senate not to fill Ginsburg's vacancy until after election Planned Parenthood: 'The fate of our rights' depends on Ginsburg replacement Progressive group to spend M in ad campaign on Supreme Court vacancy MORE's executive order on immigration and refugees to State leadership, The Associated Press reported.

The so-called dissent cable sent to State leadership is believed to be among the most popularly supported opposition statements in agency history, the AP noted.

A State official told the AP that department leadership received the memo Tuesday, one day after White House press secretary Sean Spicer Sean Michael SpicerKellyanne Conway to leave White House at end of month Pro-Trump duo Diamond and Silk launch new program on Newsmax TV The Hill's 12:30 Report - Presented by Facebook - Supreme Court's unanimous decision on the Electoral College MORE suggested those opposing Trump’s order should leave their posts.

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The AP’s source added they could not tally the exact number of signatures. Reuters later reported that about 900 people had signed the letter, citing a source familiar with the document.

“A policy which closes our doors to over 200 million legitimate travelers in the hopes of preventing a small number of travelers who intend to harm Americans from using the visa system to enter the United States will not achieve its aim of making our country safe,” a draft of the cable reads.

“This ban stands in opposition to the core American and constitutional values that we, as federal employees, took an oath to uphold."

A final version of the cable was not available.

Spicer on Monday suggested State officials displeased with Trump’s actions on immigration and refugees could surrender their jobs if they found the moves unpalatable.

“I think they should either get with the program or they can go,” he said during the daily White House press briefing, calling dissatisfied officials “career bureaucrats.”

Trump signed an executive order Friday imposing a 90-day freeze on visitors from Iraq, Iran, Libya, Somalia, Sudan, Syria and Yemen.

The measure also halts general refugee admissions into the U.S. for 120 days and indefinitely suspends the acceptance of refugees from Syria.

Trump has said the action is a necessary step to prevent terrorists from entering the country. The move has sparked backlash from Democrats and human rights organization, who say it is discriminatory toward Muslims and unconstitutional.

Updated at 3:53 p.m.