Nine hundred state department employees have signed a memo objecting to Donald Trump's executive order banning entry to the US to people from seven majority-Muslim countries.
The memo has been submitted to acting Secretary of State Tom Shannon via the department's 'dissent channel' that allows employees to share their concerns or disagreements with department policy, Reuters reports.
An excerpt from the document submitted to Shannon said the policy "runs counter to core American values of non-discrimination, fair play and extending a warm welcome to foreign visitors and immigrants".
There are also rumours circulating that some within the state department are concerned about the resignation of senior management staff last week.
However, White House Press Secretary Sean Spicer, who is aware of the state department memo, sent a message to career diplomats, warning them they could choose to "get with the programme or they can go".
Trump signed an executive order banning refugees from Syria indefinitely and suspending the US refugee programme for 120 days.
In addition, the president suspended visas for people from seven predominantly Muslim countries for 90 days, affecting people from Iran, Iraq, Yemen, Somalia, Syria, Sudan and Libya.
The introduction of the travel ban saw people detained in airports across the US last weekend despite many having previously been granted US visas or refugee status.
And protests broke out at airports where detentions occurred. Hundreds gathered at JFK Airport in New York when news broke that 12 people, including two Iraqi refugees, were stopped from entering the country at border control.