Sparked by President Donald Trump’s “zero tolerance” immigration policy and stepped-up border arrests by U.S. Immigration and Customs Enforcement (ICE), multiple government agencies are addressing an immediate and indefinite demand for new U.S. detention facilities. In addition to assessing existing government space, agencies are contacting private contractors concerning building and operating facilities, which could result in billions of dollars in new spending.

Last week, Congressional lawmakers signaled a push to increase federal funding for illegal immigrant detention center construction and operation. House Republicans drafted a compromise bill, H.R. 6136, which would allocate $6.78 billion to U.S. Customs and Border Protection for construction and operation of family detention centers along the southern border, as well as other facilities and technology. Need for the space became evident amid concern about separation of families at border sites, including a tent camp recently constructed in Tornillo, Texas, to house migrant children.

Although the bill’s passage is uncertain, Brian Turmail, spokesperson for Associated General Contractors, says it supports “providing adequate facilities for people in [U.S.] custody—both from a moral and a policy point of view.”

The U.S. Dept. of Health and Human Services, which is tasked with care of migrants detained by federal agents, has recently approached large federal contractors about building and operating detention facilities, according to a source familiar with the discussions. HHS has activated its health emergency preparedness and response unit to provide “operational and logistical expertise,” an agency spokeswoman told Politico on June 22.

Contractors were presented with a sole source contract that would include construction and operation of housing and support facilities, such as health-care clinics. Depending on scope, the contract value could reach $100 million per month, said the source. Other large firms who provide a range of infrastructure services to the U.S. government said, however, they had not been contacted related to immigrant facility work. It was not clear if any contracts have been officially offered or awarded to federal construction or emergency response contractors.

Under a Trump administration directive to eradicate “catch and release” practices, which allow arrested migrants to be released into communities until court hearings, HHS and other agencies have been pressured on housing solutions. An April Trump administration memo calls for detail on measures “to construct, operate, control, or modify … facilities to detain aliens for violations of immigration law at or near” U.S. borders.

Several military bases are being considered as detention center sites. Defense Secretary James Mattis on June 25 cited use of facilities at El Paso-based Fort Bliss and Goodfellow Air Base in San Angelo, Texas. The U.S. Navy on June 22 drafted plans to allow construction of “temporary and austere” tent camps for 25,000 migrants at facilities near Orange Beach, Ala., said Time magazine, while camps in California would accommodate up to 47,000 additional people.

ICE has explored new detainee housing options as enforcement is boosted. Arrests rose to 143,470 in 2017 from 110,104 in 2016. Florida saw a 76% increase in arrests in 2017.

Last October, ICE issued a request for information (RFI) to identify detention sites within 180 miles of Chicago, Detroit, Salt Lake City and St. Paul, Minn., that could hold up to 3,000 more detainees. ICE received 16 proposals for new, renovated or existing sites from public and private entities.

CoreCivic, one of the largest U.S. private prison contractors, proposed new facilities in Elkhart County, Ind., with nearly 1,800 beds and a 604-bed center expansion in Pahrump, Nev. It is already considering a 512-bed expansion of its detention center in San Diego County. JE Dunn, which would build it, recently applied for permits. A spokeswoman says it is too early in the proposed project to discuss construction plans.

GEO Group, the largest U.S. private prison company, proposed a new 800-bed facility in Newton County, Ind., and an existing 432-bed annex in Aurora, Colo. For both firms, ICE is their largest customer. The CoreCivic spokeswoman says the firm has “partnered” with the U.S. government to operate detention and residential facilities for more than 30 years, but she would not comment on its response to the recent ICE RFI “for obvious competitive reasons.”

The prospect of government investment in new detention facilities has grabbed Wall Street attention. Between June 19 and June 26, shares of CoreCivic and GEO Group rose 15% and 9%, respectively.