Donald Trump has fired the acting US attorney general, after she questioned the legality of his immigration ban.
Sally Yates, who had been appointed under Barack Obama, earlier ordered justice department lawyers not to enforce the president’s executive order.
In a statement, the White House said Ms Yates had “betrayed” the department.
Dana Boente, US attorney for the Eastern District of Virginia, replaces her as acting attorney general.
In a letter, Ms Yates had said she was “not convinced” that the president’s order was lawful.
“As long as I am the acting attorney general, the department of justice will not present arguments in defence of the Executive Order,” she said.
But the White House said she had “betrayed the department of justice by refusing to enforce a legal order designed to protect the citizens of the United States”.
“President Trump relieved Ms Yates of her duties,” a statement from the press secretary said.
Meanwhile, hundreds of US diplomats around the world are set to formally criticise President Donald Trump’s immigration restrictions, officials tell the BBC.
A “dissent cable” has been drafted for senior state department officials.
The White House said those complaining should “get with the programme”.
In the wake of Trump’s ban on nationals from seven Muslim-majority countries, ex-President Barack Obama has spoken out against discrimination “based on faith or religion”.
In a statement his spokesman, Kevin Lewis, said Obama was also “heartened” by the level of engagement taking place across the country.
The draft text of the dissent cable seen by the BBC says that the immigration restrictions will not make the US safer, are un-American and will send the wrong message to the Muslim world.
Such cables are not that unusual but a State Department official said that the document had been signed by “hundreds” of people, which was described as “unprecedented”.
President Trump issued the restrictions on Friday.
His executive order halted the entire US refugee programme for 120 days, indefinitely banned Syrian refugees and suspended all nationals from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen for 90 days.
Trump sacks Attorney Gen over immigrant ban
Date: