President Biden's administration on Monday ordered departments to change the terms used to describe immigration matters, including how to refer to those who enter the country illegally, Fox News has confirmed.

The administration order came in the form of memos sent to the leaders of Immigration and Customs Enforcement (ICE) and Customs and Border Protection (CBP), first reported by the Washington Post.

A Department of Homeland Security official confirmed to Fox News that several changes are being made to words that ICE and CBP will use. 

"Alien" will now be "noncitizen" or "migrant." "Alienage" will be changed to "noncitizenship." "Unaccompanied alien children" will be "noncitizen unaccompanied children." "Undocumented alien" and "illegal alien" will be "undocumented noncitizen, undocumented individual or migrant." "Assimilation" will be "integration or civil integration." "Immigrant assimilation" will be "immigrant integration." 

U.S. President Joe Biden meets with members of the Congressional Asian Pacific American Caucus Executive Committee in the Oval Office at the White House on April 15, 2021, in Washington, DC. Biden ordered changes to how federal agencies refer to immigration matters on Monday. (Photo by Doug Mills-Pool/Getty Images)

U.S. President Joe Biden meets with members of the Congressional Asian Pacific American Caucus Executive Committee in the Oval Office at the White House on April 15, 2021, in Washington, DC. Biden ordered changes to how federal agencies refer to immigration matters on Monday. (Photo by Doug Mills-Pool/Getty Images)

BIDEN DESCRIBES BORDER SURGE AS A 'CRISIS' AS HE DEFENDS REFUGEE MOVES'

Biden on his first day in office hinted that changes like this could be on the way. 

"The policy of my Administration is to protect national and border security, address the humanitarian challenges at the southern border, and ensure public health and safety," Biden said in an executive order.

"We must also adhere to due process of law as we safeguard the dignity and well-being of all families and communities. My Administration will reset the policies and practices for enforcing civil immigration laws to align enforcement with these values and priorities," he continued. 

A source with knowledge of the new policy told Fox News that senior leadership at the Department of Homeland Security had been pushing for the change for weeks before Biden's memos. 

People surround a car as it arrives carrying food donations at a makeshift camp for migrants seeking asylum in the United States at the border crossing Friday, March 12, 2021, in Tijuana, Mexico. The Biden administration hopes to relieve the strain of thousands of unaccompanied children coming to the southern border by terminating a 2018 Trump-era order that discouraged potential family sponsors from coming forward to house the children. (AP Photo/Gregory Bull)

People surround a car as it arrives carrying food donations at a makeshift camp for migrants seeking asylum in the United States at the border crossing Friday, March 12, 2021, in Tijuana, Mexico. The Biden administration hopes to relieve the strain of thousands of unaccompanied children coming to the southern border by terminating a 2018 Trump-era order that discouraged potential family sponsors from coming forward to house the children. (AP Photo/Gregory Bull)

Notably, federal law refers to an "alien" as "any person not a citizen or national of the United States." Federal law also often refers to the term "illegal aliens." 

Biden's move Monday comes as a massive surge of migrants, many of them looking to claim refugee status, has overwhelmed government facilities on the southern border. Biden referred to the situation as a crisis over the weekend.

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"We’re going to increase the number [of refugees]," he told reporters. "The problem was that the refugee part was working on the crisis that ended up on the border with young people. We couldn’t do two things at once. But now we are going to increase the number."

Biden made the comment in response to backlash over a decision not to raise the cap on the number of refugees the U.S. will take this fiscal year from the number previously set by the Trump administration. Biden quickly changed course 

Biden’s administration has until now refused to call the dramatic spike in migrant numbers, which saw 172,000 migrant encounters in March alone, a "crisis." Instead, it has referred to it as a "challenge" and blamed it on the Trump administration’s dismantling of asylum paths.

Fox News' Rich Edson, Adam Shaw and Mark Meredith contributed to this report.