The roughly 200 career diplomats who have signed memos criticizing President Donald Trump's order barring entry to refugees and residents of seven Muslim-majority countries should resign if they are not prepared to carry out the policy, the White House said Monday.

The disgruntled foreign service officers should "either get with the program or they can go," spokesman Sean Spicer said during the daily White House press briefing.

Scores of State Department employees have signed on to several memos circulating in opposition to the visa measures Trump announced last Friday.

"The president has a very clear vision. 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 prospectively, not re-actively," Spicer said. "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."

By means of an executive order, the president mandated a 120-day suspension of admission of refugees, regardless of country of origin, along with a 30-day ban on visas for residents from Iran, Syria, Iraq, Somalia, Sudan, Yemen and Libya.

The moratorium is meant to allow time for establishing what Trump calls "extreme vetting" to ensure that potential terrorists are kept out of the United States.

Trump introduced the concept of extreme vetting during the campaign after his initial proposal for a ban on Muslims entering the US brought an avalanche of criticism.

The order allows exceptions to be made for members of religious minorities who face persecution in their homelands.

In practice, such exceptions would likely benefit Syrian Christians, who have been suffering at the hands of the jihadists fighting the country's government, though the jihadists - who follow the most extreme form of Sunni Islam - likewise kill and brutalize Muslims who don't share their doctrines.

The text of one of the memos objecting to the executive order was obtained by media outlets.

The document, submitted through the State Department's official Dissent Channel, asserts that the ban will do nothing to make the American people safer.

"Given the near-absence of terror attacks committed in recent years by Syrian, Iraqi, Irani, Libyan, Somalia, Sudanese, and Yemeni citizens who are in the US after entering on a visa, this ban will have little practical effect in improving public safety," the memo says.

Trump's order "stands in opposition to the core American and constitutional values that we, as federal employees, took an oath to uphold" and "will immediately sour relations" with governments that are "important allies and partners in the fight against terrorism," the diplomats said.

State Department spokesman Mark Toner said that senior management was "aware of a Dissent Channel message regarding the Executive Order."

"The Dissent Channel is a longstanding official vehicle for State Department employees to convey alternative views and perspectives on policy issues," Toner said. "It allows State employees to express divergent policy views candidly and privately to senior leadership."

The document points out that the "overwhelming majority" of terrorist attacks in the United States are the work of native-born or naturalized US citizens.

In the cases of attacks committed by foreign nationals who entered the US on a visa, those perpetrators came from countries, such as Saudi Arabia and Pakistan, that are not on the restricted list, the diplomats added.