Nearly 200 migrant advocacy groups crafted a letter to President Biden and Homeland Security Secretary Alejandro Mayorkas demanding they close ICE detention centers and consider releasing detainees ahead of the Trump administration's plan to reverse current policy. 

The letter, which was also "cc’d" to ICE Deputy Director Patrick Lechleitner and ICE chief of staff Michael Lumpkin, called for "immediate action to protect immigrant communities while [they] still can" before their administration’s term comes to a close.

"In your remaining months in office, you have an opportunity to honor your stated commitments to the dignity and humane treatment of all people, including those who immigrate to our nation…"

Without naming President-elect Trump, the groups warned the next administration is likely to follow "through on his mass deportation plans."

‘IT’LL UPEND THE COMMUNITY': PA TOWN ROILED BY TALK OF MIGRANT HOUSING IN CIVIL WAR-ERA ORPHANAGE

The groups warned that the move would separate families and "upend the lives of millions."

Spearheaded by the Detention Watch Network, the letter included 192 other signatories, including the American Friends Service Committee, Americans for Immigrant Justice, the Center for Immigration Law and Policy at the UCLA School of Law, Human Rights Watch, Make the Road and Robert F. Kennedy Human Rights.

The latter group is run by Kerry Kennedy – not her brother, Robert F. Kennedy Jr.

By closing detention centers now, the consortium claims, it will put a stop to alleged "inhumane and abusive conditions" that purportedly include inadequate food and water, negligent medical care and deaths.

FLASHBACK: PA REPUBLICANS DRAFT BILL DIVERTING ILLEGAL IMMIGRANTS FROM SECRETIVE BIDEN-DHS FLIGHTS TO DE

"No one should be detained in these conditions. You [Biden and Mayorkas] promised to end the use of for-profit detention centers by the federal government and with over 90% detained at facilities run by private companies, this is your final chance to follow through on that promise," the letter reads.

The second of the three prongs is halting detention facility expansion efforts by way of freezing or rescinding RFPs (Requests for Proposal).

The consortium said the incoming Trump administration should not be gifted an expanded system through which to institute their countervailing goals.

"To protect families and prevent separations, you must take all possible action to prevent the incoming administration from being able to easily expand detention capacity, including by pressuring Congress to pass a reduced appropriation for immigration detention."

CLICK HERE TO GET THE FOX NEWS APP

Third, the groups pleaded for release proceedings to begin with "vulnerable populations" like migrants with physical or mental health concerns and those that have been deemed eligible for parole or Temporary Protected Status.

"People can and should be able to go through their immigration proceedings in community with the support of their loved ones and access to legal support."

"Now is the time to take decisive action to prevent catastrophe for millions of people and avoid handing the keys to an expanded and inhumane detention and deportation system to the next president," they wrote.

Other officials across the country have also warned against Trump's immigration policy proposals, with Chicago Democratic Mayor Brandon Johnson calling Trump a "threat" against "new arrivals and undocumented families… and Black families."

Fox News Digital reached out to the White House and Mayorkas for comment.