The Trump administration’s plan to collect DNA evidence from migrants detained in U.S. Customs and Borders Protection (CBP) and Immigration and Customs Enforcement (ICE) facilities will commence soon in the form of a 90-day pilot program in Detroit and Southwest Texas, CNN reported on Monday.

News of the plan first emerged in October, when the Department of Homeland Security told reporters that it wanted to collect DNA from migrants to detect “fraudulent family units,” including refugees applying for asylum at U.S. ports of entry. ICE started using DNA tests to screen asylum seekers at the border last year over similar concerns, claiming that the tests were designed to fight human traffickers. The tests will apply to those detained both temporarily and for longer periods of time, covering nearly all people held by immigration officials.

DHS announced the pilot program in a privacy assessment posted to its website on Monday. Per CNN, the pilot is a legal necessity before the agency revokes rules enacted in 2010 that exempt “migrants in who weren’t facing criminal charges or those pending deportation proceedings” from the DNA Fingerprint Act of 2005, which will apply the program nationally. The pilot will involve U.S. Border Patrol agents collecting DNA from individuals aged 14-79 who are arrested and processed, as well as customs officers collecting DNA from individuals subject to continued detention or further proceedings.

According to the privacy assessment, U.S. citizens and permanent residents “who are being arrested or facing criminal charges” may have DNA collected by CBP or ICE personnel. All collected DNA will be sent to the FBI and stored in its Combined DNA Index System (CODIS), a set of national genetic information databases that includes forensic data, missing persons, and convicts, where it would be held for as long as the government sees fit.

Those who refuse to submit to DNA testing could face class A misdemeanor charges, the DHS wrote.