The Trump administration has firmed up plans to start collecting DNA samples from migrants taken into federal custody after trying to cross the U.S. border. 

In a notice posted Friday by the Department of Justice, the administration said its new rule, which will go into effect in April, will allow the DNA data samples to be shared among federal agencies. The information will be stored in a federal criminal database managed by the FBI known as the Combined DNA Index System, or CODIS.

U.S. Customs and Border Protection officers are being trained by the FBI on how to properly collect cheek swabs, DOJ said in its notice. 

The new rule will “help to enforce federal law with the use of science,” Deputy Attorney General Jeffrey A. Rosen said in a statement.  

All non-citizens already must submit fingerprints upon U.S. entry, but the move to expand the government’s DNA database has raised alarm by immigration advocates and civil rights agencies over long-term privacy rights.

“Congress should immediately prevent any taxpayer dollars from being used to fund this xenophobic program, which seeks to further dehumanize immigrants in detention and raises significant civil liberties and privacy concerns,” Naureen Shah, senior advocacy and policy counsel with the American Civil Liberties Union, said in a statement Friday.

“Collecting the genetic blueprints of people in immigration detention doesn’t make us safer — it makes it easier for the government to attack immigrant communities, and brings us one step closer to the government knocking on all of our doors demanding our DNA under the same flawed justification that we may one day commit a crime.”

The Justice Department issued the proposed DNA rule in the Federal Register last October, and it has garnered more than 41,000 public comments. The rule would allow federal officials “to collect DNA samples from individuals who are arrested, facing charges, or convicted, and from non-United States persons who are detained under the authority of the United States.”

Under an existing program, DHS officials may request cheek swabs from a minor and an adult arriving together at the southern border if the agents suspect the pair are not actually related. The Trump administration rolled out the rapid DNA test program in response to the rising number of monthly border apprehensions last spring and claimed it would deter migrant adults from using children to temporarily stay in the United States. In January, DHS started a pilot program to collect DNA samples from individuals apprehended in Detroit and the port of entry in Eagle Pass, Texas.