The American Civil Liberties Union (ACLU) joined 12 other legal groups and immigrant rights organizations on Thursday to oppose reported new plans to expand use of private for-profit prisons to house undocumented immigrants.

The groups, which also included the Immigration Law Center of Minnesota and the National Immigration Justice Center in Chicago, wrote in a letter (pdf) to immigration officials that the housing of immigrants in for-profit prisons "cannot be accomplished without undermining due process and civil rights protections for those who will be detained."

The letter raises concerns that detainees would have little or no access to counsel in for-profit prisons, and that the safety of immigrants would be at stake.

"This sprawling system is notorious for abusive and inhumane conditions and widely criticized for its lack of transparency and accountability," wrote the groups.

Immigration and Customs Enforcement (ICE) recently asked officials in Chicago, Detroit, Salt Lake City, and St. Paul, Minnesota to identify private prisons in their cities that could be used to detain undocumented immigrants.

"ICE's intention to expand detention in areas surrounding four of the nation's largest cities is an attack on the freedom of long term residents, including Dreamers, and asylum seekers fleeing persecution in their home countries," said Lorella Praeli, the ACLU's director of immigration policy, in a statement accompanying the letter.

ICE agents detained more than 28,000 undocumented immigrants with no criminal records from January until September, starting two days after President Donald Trump was sworn in. The arrests represent a 179 percent increase from those carried out by ICE agents over the same period last year.

The Trump administration is demanding even more arrests, with a request for $1.2 billion in the 2018 budget to house 48,000 immigrants per day.

The reported attempt to expand detentions for immigrants comes a week after the GEO Group, a for-profit prison company that owns 140 facilities and won a contract from the federal government in April to open an immigration detention center, held its annual conference at Trump's golf club near Miami.

The firm donated $250,000 to the president's inaugural committee while a subsidiary gave $225,000 to a pro-Trump PAC during the 2016 campaign.

In its letter to ICE, the legal groups noted that "fueled by politics and the insidious consequences of campaign donations and lobbying by the private prison industry the immigration detention system already devalues the lives, health and safety of those jailed within its walls," and demanded that the problem not be exacerbated by the use of more for-profit prisons to house undocumented immigrants.