The federal government can't detain Central American women and children seeking for asylum as a tactic to keep others from coming to the U.S., according to a federal court's preliminary injunction in a class-action suit filed in December by the American Civil Liberties Union, brought on behalf of asylum-seeking mothers and children who are being held at facilities around the country.

Since last summer, there has been an influx of women and minors from the region who head north to escape violence, sexual abuse and other detrimental conditions in their native countries. Many of them have been found to have "credible fear" of persecution, meaning asylum could be granted, the ACLU said. 

However, the Department of Homeland Security has continuously denied their release to send a message across the border that no more people should try to come here. 

"Locking up families and depriving them of their liberty in order to scare others from seeking refuge in the U.S. is inhumane and illegal," said Judy Rabinovitz, deputy director of the ACLU's Immigrants' Rights Project, in a statement when the suit was filed. "The government should not be using these mothers and their children as pawns. They have already been through devastating experiences, and imprisoning them for weeks or months while they await their asylum hearings is unnecessary and traumatizing."

The group argued the Obama administration's "no-release" policy violated federal immigration law and regulations, as well as the Fifth Amendment, which "prohibit the blanket detention of asylum seekers for purposes of general deterrence."

With the suit, the ACLU hoped to invalidate that policy and ensure these type of cases get individualized reviews.

"In rejecting the U.S. government's argument that detention of the women and children was necessary to prevent a mass influx that would threaten national security, the court wrote that the 'incantation of the magic word 'national security' without further substantiation is simply not enough to justify significant deprivations of liberty,'" a press release from the ACLU said.