(CNN) A memo signed by 900 State Department diplomats that opposes President Donald Trump's temporary ban on refugees and citizens of seven Muslim-majority nations from entering the US has been delivered to top officials, State Department officials familiar with the memo told CNN Tuesday.

The "memo of dissent" warns that not only will the new immigration policy not keep America safe, but it will harm efforts to prevent terrorist attacks. The ban "will not achieve its stated aim of to protect the American people from terrorist attacks by foreign nationals admitted to the United States," the memo notes.

CNN first reported that a draft memo of dissent was being circulated for signatures on Monday.

White House press secretary Sean Spicer, when asked about the memo at a press briefing Monday, told the federal employees who backed it to "either get with the program or they can go."

"The President has a very clear vision," Spicer said. "He's been clear on it since the campaign. He's been clear on it since taking office, that he's going to put this safety of this country first. He is going to implement things that are in the best interest of the safety of this country ... And if somebody has a problem with that agenda then that does call into question whether or not they should continue in that post or not."

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